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Officers, Committees 3-5 

Radio Movies. By C. Francis Jenkins 7 

How Theaters Should Be Ventilated. By F. R. Still 13 

Artistic Utihzation of Light in Motion Picture Photog- 
raphy. By Wiard B. Ihnen and D. W. Atwater 21 

The Use of Color for the Embellishment of the Motion 
Picture Program. By L. M. Townsend and Lloyd 

A. Jones 38 

Static Markings on Motion Picture Films. By J. I. Crabtree 

and C. E. Ives 67 

An Improved Sector Wheel for Hurter and Driffield Sensi- 

tometry. By M. Briefer 85 

The Manufacture of Tungsten Incandescent Motion Picture 

Lamps. By R. S. Burnap 90 

A New Reflectometer. By Frank Benford 101 

Color Photography Patents. By WiUiam V. D. Kelley 113 

Report of the Papers Committee 120 

Announcements 121 

Advertising Section 123 

Number Twenty-one 

MEETING OF MAY 18, 19, 20, 21, 1925 

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OF THE '"^'i " 


Number Twenty-one 

MEETING OF MAY 18, 19, 20, 21, 1925 

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Copyright, 1925, by 

Society of 

Motion Picture Engineers 

New York, N. Y. 

SEP ^^1,^25 

©C1A864433 :.^ 

Papers or abstracts may be reprinted if credit is given to the Society of 
Motion Picture Engineers. 

The Society is not responsible for the statements of its individual members. 

P. M. Abbott 




President . 
L. A. Jones 

Y ice-President 
A. F. Victor 

Wm. C. Hubbard 

L. C. Porter 

Board of Governors 
L. A. Jones 
L. C. Porter 
Wm. C. Hubbard 
J. A. Summers 


J. C. Kroesen 
J. H. McNabb 
F. F. Renwick 
J. C. Ball 


J. A. Ball 
J. I. Crabtree 

J. G. Jones 

L. G. Moen 

J. C. Kroesen 

W. C. Hubbard 

R. J. Pomerov 
L. C. Porter " 

J. H. McNabb 

A. C. Dick 
J. E. McAuley 


C. E. Egeler, Chairman 
P. R. Bassett 
Rowland Rogers 

Standards and Nomenclature 
L. C. Porter, Chairman 
Hermann Kellner 
F. F. Renwick 

J. C. Kroesen, Chairman 
R. S. Peck 
Wm. Sistrom 

Wm. F. Little, Chairman 

Geo. A. Blair, Chairman 
S. C. Rogers 
H. A. Campe 

Coast Section 
J. A. Ball, Chairman 
Wm. V. D. Kelley 
Wm. Sistrom 

F. F. Renwick, Chairman 
J. A. Ball 
Herbert Griffin 

I. L. Nixon, Chairman 
Roger M. Hill 
Earl J. Dennison 
Wm. C. Kunzman 

Wm. T. Braun 

F. H. Richardson 

C. M. Williamson 

J. A. Summers 

W. R. Rothacker 

Geo. A. Mitchell 

M. W. Palmer 

W. W. Johnstone 
J. I. Crabtree 


C. Francis Jenkins* 

THE year 1824 saw the beginnings of a photographic process for 
pictorially recording persons and places; to be visually exhibited 

later, and at a distance. But the persons and other animates 
in the picture were without movement, so later, when differentiation 
required it, w^e called these pictures "stills." 

Some thirty-five years ago I came to Washington with a rather 
definite idea that I could add to the record and reproduction, the 
activity of the scene, the movement of .the persons in the picture. 

In 1892 my work had so far progressed that I was able to project 
onto a silk handkerchief pictures with action depicted therein. I used 
an oil lantern, for illumination, bought of J. B. Chamberlain, a lantern 
in form strikingly like some of those illustrating the presidential 
address of Mr. Lloyd A. Jones as it appears in the Transactions of 
the Chicago meeting of this Society. 

The picture ribbon was made of kodak roll film, bought of E. J. 
Pullman, a pioneer Eastman photo supply dealer, and slit into narrow 
strips, and spliced into a single length, in the dark room. 

Photographer I. D. Boyce developed most of both the camera 
negatives and the prints therefrom. 

The first "motion picture artist" who performed before my 
camera was Arthur J. McElhone, athlete and stenographer. 

In 1894, with the assistance of electrician D. N. Washburn, 
an arc lamp was fitted to the machine and life-size pictures were 
projected before many friends, one report of which appears in the 
Photographic Times, July 6, 1894, copies of which can be found in 
most Kbraries. 

The next year I built a motion picture theatre in Atlanta, Ga., 
financed by Thomas Armat. The admission charged was twenty-five 
cents, the first sale of tickets, for a theatre built exclusively for 

To all my various machines I gave the fanciful name "Phanto- 
scope," and many newspaper accounts refer to my machines b}^ this 

In order to get sufficient screen illumination, (1) this apparatus 
gave the film a step-by-step motion, with a relatively long rest 
period, during all of which time the film was illuminated. 

To reduce to a minimum the strain on the film by reason of this 
jerky motion at the exposure aperture, (2) means were provided 
to create a loop in the film between the intermittent feed devices 
and the unwinding roll of picture film, 

* Jenkins Laboratories, Washington, D. C. 


8 Transactions of S.M.P.E., August 1925 

These two fundamentals in exactly the arrangement in that old 
1894 machine have been in use in every projector in every theatre 
the world over to this very day. 

So, as photographic matters now stand, that early Daguerro- 
type process of a hundred years ago has been refined and developed, 
as the years have gone by, until to the original photographic record 
has been added (1) stereoscopic plasticity, (b) natural color, (c) the 
living action, and (d) appropriate sound. 

The addition of smell and taste and touch has been proposed, 
although I hardly think I shall live to clasp hands with my friend 
across the continent. 

Beside the intermittently moved motion picture film mechanism 
described above, there has been but a single other method attempted, 
namely, continuous running film, preferably with full uninterrupted 
illumination, which I made the subject of U. S. Patent No. 560,800, 
where a series of lenses run with the film. 

I mention this here for the reason that it is the scheme I em- 
ployed when I susbstituted radio for film to carry movies into the 
home, notice of the initial accomplishment of which appeared in 
the Washington Star for June 13, 1925, and sent to other papers by 
the Associated Press at the time. 

To lay down a convenient foundation for an understanding of 
our subject, let me mention two basic facts; namely, (a) that speed 
is the only difference between magic lantern "still" pictures and 
projected motion pictures; and (b) that our radio picture is built 
up by a point of light moving in successive parallel adjacent lines 
until the picture is complete. 

Don't you remember that mother entertained us on a winter 
night by covering a penny with a piece of white paper, and rubbing 
across it with the unsharpened end of a lead-pencil she made a 
picture of the Indian appear? 

Well that is exactly the way we make pictures by radio, except 
that instead of the pencil of lead we employ a pencil of light, and 
that radio builds up the blacks of the picture just as did the humps 
on the penny. 

By speeding up the process to a persistence-of-vision rate, say, 
sixteen complete pictures per second, we get Movies by Radio. 

And that's exactly the way we do it. Perfectly easy, isn't it? 
You can go home now and do it yourself. 

But if I suggest that my thirty-five years experience in motion 
picture development has materially facilitated the attainment of 
radio movies, perhaps I may be permitted to mention a few essentials 
to aid you in more quickly solving the problem. 

First of all, then, you must make that impossible shape in glass, 
the Prismatic Ring, for I now believe that Motion-Pictures-by-Radio 
is not likely ever to be accomplished without them. 

The function of the Prismatic Rings is to sweep the image of a 
point-like source of light across the picture-receiving surface in 
paralleladjacent lines until the whole surface is covered. 

Jenkins — Radio Movies 9 

The Rings are set with their diameters at right angles where the 
hght passes through the overlapped Rings. One of the Rings draws 
the lines, while the other distributes the successive lines over the 
picture surface. The Ring that makes each line, rotates, say, four 
hundred times to the other one's once, one turn of the latter com- 
pleting each single picture frame. 

It must be remembered that the incoming radio-carried current 
is fluctuating the lamp to build up areas of light and shade; and it is 
lights and shadows out of which our picture is made, of course. 

As the picture is built up line-by-line at the receiving station, 
obviously it must be taken to pieces hne-by-line at the sending station. 

This is done by projecting the picture through other Prismatic 
Rings, which, in rotation, sweep the picture many times across a 
light-sensitive cell. The picture is thus- sliced up, figuratively, into 
slides, like a bacon cutter in the market, each slice showing light and 
dark. The varying light values of each slice falling on the cell are 
converted into corresponding values of electric current; which, put 
on a radio carrier wave, cause the light source at each receiving set 
to fluctuate in intensit}^ correspondingly. 

If, then, all the receiving stations are in sjmchronism with the 
sending station the light values fall in the proper places on each 
picture receiving screen, and the motion picture at the sending 
station is duplicated in a thousand homes. 

The machines make a complete picture frame every sixteenth 
of a second, continuously, and we have motion pictures on a plain 
white surface. But if the slow Prismatic Ring turns over once in 
six minutes to make a "still'' picture, then a photographic negative 
must be used to receive and record the light values. 

We have made some very superior pictures by radio in six 
minutes, of which I vn]l show you examples presently. However, 
it is a "whale-of-a-jump" from a six-minute picture to a picture in 
one-sixteenth of a second; but it can, and is being done daily. 

To be sure, on account of the speed involved, I had to substitute 
a lens-disc for one of the Prismatic Rings, the fast one, but this lens- 
disc worked with the other Ring, the slow rotating Ring, perfectly, 
and Radio ^Movies and Radio Vision are both accomplished facts. 

The radio Vision receiving set and the Radio IMovies set are 
identical, and one may, therefore, see in one's home what is happen- 
ing in a distant place (an inaugural parade, football, or polo game, 
and we call it Radio Vision), or one may see the motion picture then 
running on the screen of a distant theatre, or in our broadcasting 
studio (and we call it Radio Movies). 

Perhaps at a later convention meeting I may have the privilege 
of demonstrating the process and mechanisms before you. 

Though spectacular, theoretically it is not a very difficult thing 
to do; speech is carried by radio, and sight should just as easily be 
so carried. 

10 Transactions of S.M.P.E., August 1925 

To get music by radio, a microphone converts sound into 
electrical modulation, which carried by radio to a distant place is 
there changed back into sound and we hear the music. 

To get pictures by radio our sensitive cell converts light into 
electrical currents, and at radio distances changes these currents 
back into light values; and we see the distant scene. 

To further show the close relation, I might add that in receiving 
sets these same electrical values can be put back either into sound 
with headphones or into light with a radio camera; although, I admit 
we don't make much sense out of it when with headphones we listen 
to a picture. 

Radio Vision is now a daily demonstration, and while it is not 
yet finished and ready for your use, it soon will be, for if I should 
be obliged to stop for lack of funds to carry forward the necessary 
refinement, some one else would complete the work, for the public 
is now ready for Visual Radio entertainment in the home. 

I am indebted to my friend Professor D. McFarlan Moore for 
a word name for this new device, namely, telorama, and telorama- 
phone. I didn't particularly like the name when he first urged my 
adopting it, but since I have become more accustomed to the sound, 
I don't mind it so much. I remember it stunned me the first time I 
tried to introduce Mrs. Jenkins as "my wife," but it didn't sound so 
awful after awhile. 

In due course, then, folks in California and in Maine, and all 
the way between, will be able to see the inaugural ceremonies of their 
President, in Washington; the Army and Navy football games at 
Franklin Field, the struggle for supremacy in our national sports, 
and after eighteen years of trying see Walter Johnson win. 

The new machine will come to the fireside as a fascinating teacher 
and entertainer, without language, literacy, or age limitation; a 
visitor to the old homestead with photoplays, the opera, and a direct 
vision of world activities, without the hindrance of muddy roads 
or snow blockades, making farm life still more attractive to the 
clever country-bred boys and girls. 

Already audible radio is rapidly changing our social order; 
those who may now listen to a great man or woman are numbered 
in the millions. Our President frequently talks to practically the 
whole citizenship of the United States at the same time. 

When to this audible radio we add visible radio, we may both 
hear and see great events; inaugural ceremonies, a football, polo, 
or baseball game; a regatta, mardi gras, flower festival, or baby 
parade; and an entire opera in both action and music. 

And from our easy chairs by the fireside, we stay-at-homes can 
watch the earth below as that great ship, the Shenandoah, carries 
our flag and a broadcasting lens, over the mountains and plains, the 
cities and lakes, of our wonderful country. 

A speaker representing the Westinghouse Company, at the last 
Radio Conference, predicted that we may all listen to the next 

Jenkins — Radio Movies 11 

Olympic games. But I objected that the entertainment should only 
be addressed to the ear, why shouldn't we stay-at-homes also see 
the games. It seems to me a reasonable request. Radio is carrying 
pictures today just as it is carrying sound. Logically, then, we should 
both see and hear the next Olympic games. 

T\Tien the teloramaphone is made generally available, then 
pictures at the fireside sent from such distant world points will be 
the daily source of news; the daily instructional class; and the eve- 
ning's entertainment; and equally the long day of the sick and shut- 
ins will be more endurable, and life in the far places less lonely, for 
the flight of Radio is not hindered by rain, or storm, or snow blockades. 

Before I put on the lantern pictures I should like to pay tribute 
to the unselfish assistance received from the General Electric and 
Westinghouse Electric Companies; and -particularly to mention the 
loyalty and confidence of Mr. L. C. Porter, Professor D. McFarlan 
Moore, and Dr. W. R. Whitney, of the General Electric Company, 
and of Mr. H. P. Davis, Vice-President of the Westinghouse Electric 
& Manufacturing Co., and of Mr. S. M. Kintner, head of the Re- 
search Laboratory. 

And I think it is only fair that I should also mention the splendid 
young folks who are my laboratory assistants, Sybil Almand, Florence 
Anthony, John Ogle, James Robinson, Stuart Jenks and Thornton 
Dewhirst, to whom in no small measure credit is due for Radio Movies. 

And me? Oh, I am the fellow who sat by and watched them at 
work; scratched for money to pay rent and salaries; and looked as 
wise and dignified as possible when we had distinguished visitors. 


Mr. Richardson: Is there a probability that the receiving 
mechanism optically and mechanically can be made at a reasonable 
cost, and can it be mechanicall}^ and optically so made that almost 
anybody can operate it? 

Mr. Jenkins: Anybody can easily operate it and the price 
we believe the}^ can be sold for when available is about SI 50 for the 
machine which will give you motion pictures. I am going to use 
the word "motion pictures" as illustrating pictures on the screen on 
which the pictures we send you are put, whether they are sent from 
the ball game or from the theatre screen. When we add music or 
appropriate sounds to the same set it may increase it SIOO. These 
are tentative prices based on what we now see of the machine as it 
will be marketed — S150 for motion pictures alone, and for the 
"Teleramaphone" which adds sound it will probably be S250, i. e., 
both music and action. 

If you will give me three or four minutes more, with your 
permission I will tell you why we can send music and motion pictures 
on the same wave-length. All superheterodjme radio sets of today 
have two detector tubes, one for 60,000 cycles, and another for the 
speech or music, each amplified three or four times. This is the 
usual construction. So I said, "Why can't we send pictures on the 
first half of the superheterodyne set that we can't hear and then 
send music on the audible c^^le?" So that we have our carrier wave 
modulating a 60,000 cycle picture wave which we further modulate 
for audibility and we get the music also. It is not difficult but only 
tedious. In the laboratory we can do this, but at the Naval Station 
we have been trying to do it for a week. 



F. R. Still* 

MOST of the owners of theatres and the engineers who design 
heating and ventilating plants for theatres have largely failed 
to consider the wide difference in the requirements of a standard 
theatre and moving picture theatre. There is hardly any more re- 
semblance in their respective requirements than there is in the pro- 
visions to be made to ventilate a school house or a church, yet it has 
been the general practice to apply the same proportions and employ 
about the same standards of apparatus for both types of theatre 

The Standard Theatre is occupied for perhaps three hours at a 
time usually after sun-down, during six days of the week, and is 
closed throughout the warm summer months. An adequate and 
dependable heating system is, of course, necessary to maintain a 
comfortable temperature in cold weather. The usual standards for 
ventilating auditoriums will apply to such theatres, and will prove 
to be entirely adequate under normal weather conditions. 

In winter weather there is very little moisture in the outside air. 
As the temperature of the outside air is raised to the room tempera- 
ture, the relative humidity is lowered ; hence the air should be humid- 
ified in cold weather so as to maintain 40 to 45% relative humidity 
inside the building. 

In the late spring and early fall, the outside temperature and 
humidity sometimes become almost as high as during the summer. 
During these periods it may become uncomfortable inside, but these 
periods are so short that artificial cooling is hardly warranted. 

The Moving Picture Theatre is an altogether different problem. 
It is occupied, more or less to full capacity, for twelve hours per day, 
every day in the week including Sundays, and every week throughout 
the year. The heating and ventilating plant must be designed to 
meet the requirements of the two extremes of outside weather condi- 
tions, viz., winter and summer, both of which extend over several 

In the winter time, the place must be heated to a comfortable 
temperature. The air must be clean and pure, devoid of odors and 
humidified to a comfortable extent. 

In the summer time, both the temperature and the relative 
humidity must be reduced to get satisfactory results. It is impossible 
to reduce the temperature of the air discharged into the building 
very much below the normal inside temperature without causing dis- 

* Vice president, American Blower Co., New York City. 


14 Transactions of S. M.P.E., August 1925 

comfort ; hence it becomes necessary to provide for the circulation of a 
very much larger volume of air in the summer than during the winter 
to absorb the natural heat radiated from the walls, the roof, the lights 
and the people. If this large volume is properly distributed and dif- 
fused over the whole area of the house, an excellent air motion can 
be maintained which has a most marked effect on the comfort of the 
audience in warm weather, because it feels as though the temperature 
is much lower than it really is, instead of feeling chilly and clammy 
as is so noticeable in those theatres wherein an attempt has been 
made to cool them with a small volume of recirculated air which has 
been lowered to a very low temperature so as to absorb the heat. 

It is not infrequent that the volume of air required to maintain 
comfortable conditions in a Moving Picture Theatre in the summer 
time will be two or more times the volume of air that would be 
normally provided for a Standard Theatre of the same size, yet we 
see plans and specifications right along wherein this difference is 
entirely ignored, and no greater provision is made for a movie house 
than would be made for a Standard Theatre. 

There are two reasons for this. One is that few designers under- 
stand exactly what sort of an atmospheric condition should prevail to 
attain perfect comfort. The other is, that the majority of the archi- 
tects and engineers did not appreciate fully the great difference there 
is in the requirements of a Standard Theatre and a Moving Picture 
Theatre. They knew that certain standards as applied to the older 
type of theatres gave reasonably satisfactory^ results, and it naturally 
followed in the course of their everyday operations that the same 
would apply to moving picture theatres. 

It is only within the last two or three years that any reliable 
data has been available to work with which would indicate what the 
atmospheric conditions should be inside of a building to attain the 
same comfort that a person feels on a fine June day in the open 
country. Apparatus was available to maintain any temperature, any 
relative humidity and produce any air motion, but the right com- 
bination was not known. Not until the American Society of Heating 
and Ventilating Engineers established a Research Laboratory at the 
U. S. Bureau of Mines, Pittsburgh, and induced the U. S. Department 
of Public Health Service to take up the investigation of this subject, 
was any real progress made. This was started nearly seven years 
ago. The work is now nearing completion, but the whole scope of 
the problem required nearly five years of constant experimentation 
and investigation before any definite results were available. 

Some years ago Dr. Leonard Hill of London, England, made an 
investigation of the wet and dry bulb temperatures all over the 
world. He took particular note of those atmospheric conditions which 
seemed to be most comfortable. As a result of his observations he 
found the prevailing wet bulb temperature was somewhere between 
54° and 58°, and that the dry bulb temperature must vary, depending 

Still— How Theaters Should Be Ventilated 15 

on the wind velocit}^ and the occupation of the subject, to attain 
perfect comfort. 

With this as a starting point the Research Laboratory at Pitts- 
burgh persuaded Dr. Savers of the Department of Pubhc Health 
Service, Washington, D. C, to take charge of the experiments, to 
definitely determine the reactions of human beings to varying wet 
bulb temperatures, dry bulb temperatures, air velocities, when naked, 
lightly clothed and normally clothed; when at rest, at light work, 
and when vigorously exercising. 

As the greatest demand for refined ventilation is in those build- 
ings where the occupants are at rest, the work so far completed covers 
that condition quite fully. One or two examples will illustrate how 
the data obtained may be applied. 

Supposing a person normally clothed is exposed to a dry bulb 
temperature of 71° and a relative humidity of 30%; the wet bulb 
will be 54°. Again supposing the dr}^ bulb temperature is 60° and the 
relative humidity is 76%; the wet bulb temperature will be 55.75°. 
Either of these temperatures will afford about the same degree of 
comfort in still air. 

In the first instance if, instead of still air, the air velocity should 
be 100 ft., the effect will be the same as though the apparent dry 
bulb temperature was only 69°; at 200 ft. velocity the apparent 
temperature will be 68°; at 300 ft. velocitv the apparent temperature 
will be 66°. 

In the second case, if the velocity should be 100 ft. the apparent 
temperature would be 68°; at 200 ft. velocity the apparent tempera- 
ture would be 65°; at 300 ft. velocitv the apparent temperature would 
be 63°. 

If a person was stripped to the waist, under these air motions 
he would soon shiver as though it was 10° to 15° colder. 

These citations are given merely to indicate the scope of the 
work being done and to impress upon you that real comfort can not 
be obtained by merely heating or cooling air. There is a relationship 
existing between the wet and the dr}^ bulb temperatures which must 
be maintained in a still atmosphere. As soon as an air motion is set 
up, the relationship changes and it varies more or less as the air 
motion increases or decreases. 

Another important factor that affects the comfort of many per- 
sons is odors. To what extent the effect they have on some people 
is physiological or psychological has not yet been definitely de- 
termined. A strong odor of musk in a warm, unventilated room has 
been known to cause some women to faint, yet others enjoy it. 
Some people can live and thrive in the midst of conditions that are 
to others most abhorrent and, perhaps, nauseating. 

Odors can always be completely eliminated by passing the air 
through a properly proportioned air washer. Adding a heater to 
warm the spray water, the humidity of the air can be increased and 
by cooling the water the humidity can be lowered. With suitable 

16 Transactions of S. M.P.E., August 1925 

automatic controlling instruments any desired relative humidity 
can be obtained that is best suited for the air motion maintained 
regardless of outside atmospheric weather conditions, in addition 
to the complete elimination of the odors and the removal of the 
floating dust and dirt in the air as previously mentioned. 

Many owners of theatres fail to realize the value in an air 
washer. The preservation of the decorations and furnishings will 
alone make it a good investment in many cities, even if its value 
as an essential adjunct to the ventilating plant is entirely discounted. 
But the time is fast approaching when there will be no argument 
about the necessity of properly humidifying and cooling the air. 
The theatres that are so equipped will soon become generally known 
and the public will demand the same comfortable atmospheric con- 
ditions in all of them by refusing to patronize the houses which have 
failed to put in such equipment. 

While the building and operation of theatres is a business proposi- 
tion from the standpoint of the owner or manager, it is a place of 
recreation and pleasure for those who patronize them, and as the 
patrons begin to realize it is unnecessary to endure uncomfortable 
atmospheric conditions they are sure to seek out and favor those places 
where they are comfortable. 

Architectural beauty, pleasing and colorful decorations, com- 
fortable roomy seats and good accoustics have all come about be- 
cause the public has shown it appreciates such things, but none of 
them would count for much if the place smelled badly, or the at- 
mosphere was close and stuffy, or if it became too warm, or it was 
drafty and cold. 

While there are now quite a number of theatres equipped with 
ventilating plants of ample capacity to maintain a reasonable, com- 
fortable, thermometric temperature throughout most of the audi- 
torium, we only know of two buildings in which the designer ap- 
parently fully recognized the opposite requirements during the cold 
and warm weather by arranging for a reversal of the air movement 
during the two periods. That is, the warm air enters the house 
through the floor, beneath the seats in the winter and finds an exit 
mostly through the ceiling. In the summer the cool air is admitted 
through the ceiling and is largely removed through the floor beneath 
the seats. 

Cold air striking a person shortly after it escapes from the 
ducts always causes great discomfort and complaint. Hence it must 
be introduced at a considerable distance from the occupants. On 
the other hand, the warm air coming into immediate contact with the 
occupants in cold weather is very agreeable provided the velocity 
of the air is not excessive. 

In both of the theatres referred to, this reversal of air currents 
is accomphshed by shifting two or three dampers. Of course the fans 
are speeded up to get a larger volume in the summer than is required 

Still — How Theaters Should Be Ventilated 17 

in the winter, and the velocity can be very much greater owing to 
the air entering at a distance so remote from the audience. 

The question uppermost in your mind is hkely "What does it 
cost to install an efficient ventilating plant such as has been herein 

That is a very difficult question to answer with any degree of 
definiteness, because there are so many variables in the construction 
and location of the buildings, the climatic conditions prevailing in 
different parts of this country, the size of the building, its exposure 
and the type of refrigerating plant used. 

It may be stated that it requires approximately from 75 to 100 
tons of refrigeration per thousand people, and a complete ventilating 
plant with refrigeration will cost anywhere from $200.00 to $800.00 
per ton refrigeration. 

In other words, a house seating 3000 people, with a ventilating 
plant designed to cool it to 70 degrees when it is 95 degrees outside, 
recirculating 80% of the air would require about 285 tons capacity. 
This is based on an initial dewpoint of 40 degrees. With the same 
dewpoint and outside temperature, if the inside temperature is 85 
degrees instead of 70 degrees, it will require about 267 tons of re- 
frigeration, or about 6)^% less. 

With the same outside temperature and a dewpoint of 50°, to 
maintain 70° inside will require about 284 tons, and to maintain 85° 
inside will require only 250 tons capacity. Thus there is only 15% 
difference in the extremes of refrigeration required in these examples, 
which are fairly representative of conditions encountered in the sum- 
mer in this section of the country. It also indicates the possibility 
of obtaining very comfortable temperatures even when it is impossible 
to reach an anticipated low dewpoint. 

Such a plant would cost from $50,000 to $85,000 complete. This 
includes blowers, motors, heating surface, humidifying equipment, 
pumps, ducts, automatic controlling instruments, etc., all installed on 
foundations and adjusted ready for use. 

The next question is the testimony of those who have tried it. 
The lowest estimate we have obtained from any manager is an average 
increase of 2634% in the attendance of patrons during the months of 
June to August inclusive. The maximum report we received was a 
statement that the house had always lost money during the hot 
weather; that they afterward advertised daily the outside and inside 
temperatures and people actually admitted that they came quite as 
much to get cooled off as they did to see the show. This may not 
speak very well for the show, but it indicates whether or not it pays 
to make such an investment. 

In Minneapolis and St. Paul there is a basin of very cold water 
at depths varying from 400 ft. to 800 ft. This water is supposed to 
come through a stratification leading from Lake Superior. 

The Astor Theatre in St. Paul is so located that it gets a severe 
exposure from the sun and hot winds blowing in from the prairies. 

18 Transactions of S.M.P.E., August 1925 

The attendance at this house fell off to almost nothing in the summer. 
A cooling system was installed, using artesian water from the basin 
mentioned. The house not having been built to admit of a highly 
efficient plant being installed, maximum results could not be obtained, 
but the conditions are so improved that the manager claims there is 
hardly any noticeable difference in the attendance, summer or winter. 

The State Theatre in Minneapolis is very well known to all 
theatre owners in the middle west as being about the first theatre 
wherein a real effort was made to install an up-to-date cooling plant. 
Cold water is obtained from the same basin above referred to at a 
depth of about 800 ft. The temperature of the water is 49°. The 
satisfaction obtained from this installation was so marked that many 
owners, managers, architects and engineers have visited it from all 
parts of the country. It is our belief that this plant has has a greater 
influence on the attitude of theatre owners toward cooling plants than 
anything that had been done up to that time. 

Cold water not being obtainable in most places it is necessary to 
cool it artificially by a refrigerating plant. This adds greatly to the 
cost. In fact, it becomes the most expensive unit of the entire system. 

Man3^ other instances could be cited than the two referred to, but 
both being pioneers in that line and still giving a good account of 
themselves, it seems hardly necessary to mention that about fourteen 
or more other houses have been since equipped with cooling plants 
using refrigeration to cool the water. 

We hope that out of this discussion you will have been convinced 
of the coming and certain necessity for cooling theatres; that the 
problem must receive special treatment by somebody who is conver- 
sant with proper relative atmospheric conditions and how to obtain 
them so that the results will be entirely satisfactory; that the cost, 
though considerable, is not prohibitive, and in fact that it costs less 
than many other things that go into theatres from which less returns 
can be measured on the investment. 

In closing, we want to suggest that good, substantial, efficient, 
dependable apparatus is the cheapest in the end, but that such equip- 
ment is incompatible with low initial costs. Anything on which so 
much dependence is placed is deserving of only the very best equip- 
ment on the market. Therefore, place your problem in the most 
competent hands you know of, and buy only the best equipment. 
You will then be satisfied and be sure of success from your investment, 
all other things being equal. 


Mr. Braun: As Mr. Still says, refrigerated air should not be 
introduced through the floor. I remember one place where refrigerated 
air was introduced by means of mushrooms. After the performance 
it was necessary for the patrons to go through a number of foot 
exercises to warm up. In how small a theatre would such a re- 
frigeration system be practical from the cost standpoint? Has Mr. 
Still any ideas for smaller theatres, say a 1500 seat house? How 
would he take care of getting more air in the summer in the small 

Mr. Briefer: I understand that about 80% of the air is re- 
circulated. Has anything been done to safeguard the health of the 
people attending a theatre in which they are recirculating 80% of 
the air — that is, in connection with purifying the air. 

Mr. Still: In the TivoH Theatre I believe intakes are provided 
in both the ceiling and the floor with dampers arranged so that the 
circulation may be reversed. In summer it is admitted overhead and 
taken out through the floor; in the winter it is reversed. ^ That 
answers the second question as to how you can get more air into 
the small theatre in the summer without discomfort. You need air 
motion in the summer to obtain comfort regardless of the tem- 
perature; the greater volume gives you the required air motion. 
As an apt illustration: in a dead, stagnant atmosphere in hot weather, 
the moisture given off by the skin is not evaporated, and the blood 
pressure rises, hence your body temperature rises. That is why you 
buy disc motor-driven fans to blow air on you in your offices and 
homes; you feel cool because the moisture from your body is evapor- 
ated by air motion, and the body temperature is thus lowered. If 
you will test your temperature on a hot day you will find it is above 
normal when the air is extremely hot and stagnant. At Pittsburgh, 
four physicians that Dr. Sayers sent down from Washington have been 
experimenting on this problem. These men have subjected them- 
selves to conditions that have almost caused death in order that they 
might definitely determine these reactions. The body temperature 
rises above 97.5° when the surrounding air is near that temperature, 
and continues to rise as the relative humidity increases. If you are 
surrounded for any length of time by a dry bulb temperature of 97.5° 
and a wet bulb temperature of 97.5°, you will die. The closer the wet 
bulb is to the dry bulb reading, the more uncomfortable you are; 
the farther apart they are, the better you feel. Naturally, there is a 
point below 50% saturation where you need more heat as shown by 
the dry bulb thermometer for a given wet bulb temperature, and the 
dry bulb must go higher as the air motion is increased, due to the 
evaporation from the skin . 


20 Transactions of S.M.P.E., August 1925 

As to the condition of recirculated air: there used to be an old 
theory that CO2 is the biggest bugbear to be dealt with. We have 
more recently found that it is harmless. Too much CO2 causes us to 
breathe faster. We now measure the CO2 simply to determine the 
efficiency of the distribution of the air. The oxygen in the air is what 
is needed to support hfe. We don't require for our physical welfare 
anything like the volume of air we regularly put into buildings, but 
we do need the volume so as to get it thoroughly distributed so that 
it may reach everybody alike. 

Due to the experiments and the information gathered at Pitts- 
burgh, engineers in two cities — Detroit and St. Louis — have been 
induced to build some schools so that the air could be recirculated. 
Continuous examinations and tests have been made, and it has been 
found after four years observation that the children are as well off 
as they are in any of the schools of those cities. In those buildings 
only 25% of fresh air is used, though 30 cubic feet per pupil per minute 
is circulated. In St. Louis they also have ozone machines in nearly 
all the schools in that city — I think they have something like 150 
schools so equipped. Ozone has a very peculiar odor, and a strong 
bactericidal effect. When it is too concentrated, it attacks the mucous 
membranes of the throat, eyes, and nose, but we are able with an 
ozone machine in front of an air washer to recirculate the air without 
any odor resulting, and without the bad effects mentioned. It also 
has a very decided bactericidal effect on the water, and apparently 
adds enough oxygen to make up the normal requirements. From a 
practical standpoint, I believe we can recirculate practically all the 
air, with a tremendous saving in coal. With proper ventilating 
equipment in our school buildings using outside air entirely, you might 
say that for every four pounds of coal, three are burned for ventila- 
tion and one for heating, so that by recirculating we can cut this down 
to one and a half pounds or two pounds. 

Mr. Hertner: In speaking about washing the air you said it 
furnishes some of the oxygen to the air. Is the washing water re- 
newed, or how does it regain oxygen after some is removed? 

Mr. Still: There is always a make-up supply to the tank to 
replace the water evaporated. You thus get nearly as much oxygen 
without any ozone as if all of the air supply came from outside. 
What the provisions for ventilation may be makes some difference, 
of course, but the amount of water evaporated from an air washer 
will usually put back the amount of oxygen needed. There is from 
six to eight times as much oxygen in the average air supply as is 
needed for respiration, and what is consumed comes back by the 
evaporation of the water sprayed into the air. 

Mr. Briefer: You refer to dissolved air in water, I suppose? 

Mr. Still: Yes. 


By Wiard B. Ihnen and D. W. Atwater 

THE merit of a motion picture depends absolutely upon its filming, 
A poor picture, although it may be shown by a skilled projec- 
tionist amid beautiful surroundings to the accompaniment of 
appropriate music, is still a poor picture; a good picture can un- 
doubtedly gain much by an artistic presentation, but no amount of 
artistry in projection can make a poorly filmed picture any better 
than it was when it left the studio. 

It is in the studio, then, that the worth of a picture is determined, 
and, as lighting is the very essence of photography, studio lighting 
has become one of the most important fields of the industry. If the 
filming of a picture were merely a mechanical process, it would be 
easy enough by our modern methods of illumination to flood a scene 
with enough light. But rather than being a mechanical process, 
it is more or less of an art, and the questions involved are not merely 
the amount of light, but the direction and the shading of the light. 
Every picture involves its own distinct problems, and the field 
of studio lighting is practically limitless. The lighting values for 
each scene must be adapted to it, just as the characters' costumes are. 
It would be impossible to lay down any fixed rule of thumb for lighting 
a picture, or to attempt to cover all the possible problems which arise. 
This paper can take up only a few of the ways in which lighting 
effects can be employed to create an artistic picture. 

Specialization makes efficiency without which the modern world 
could not exist. Director, art director, cinematographer,- whoever 
assumes the responsibility of fighting a picture should be free of all 
problems not essentially his, leaving him more time to visualize and 
concentrate on the problem of making beautiful and imaginative 
motion pictures which are truly works of art. His scientific (i.e., 
design and development of equipment) thinking should be done by 
the engineer. 

Aside from development of equipment, the engineer might go a 
step farther and help work out the proper colors of materials employed 
in making costumes and settings. Costumes are elaborate and 
expensive, usually in keeping with each scene and certainly very 
beautiful. This beauty of color and contrasts of light and dark are 
many times lost in the picture because the particular combinations of 
colors and hues do not register in the picture. 

We can all remember how movies were made in the early days, 
practically every scene being taken under a flood of dayhght. Studios 
had great expanses of glass roof and as long as the sun remained 



Transactions of S.M.P.E., August 1925 

bright, pictures could be taken. Let a cloud obscure the sun or a dark 
day come along and production was at a standstill. Electric lighting 
has gradually supplanted the daylight pictures until we find a com- 
plete reversal of the earlier conditions. Today everything possible 
is done under artificial light and we find the old glass roof studios 
painted over in mourning. 


Fig. 1. — A stage setting of more than twenty years ago — obviously painted 
scenery with absolutely no depth or character. 

It is, of course, not fair to charge up all the difficulties en- 
countered in lighting a picture to equipment and any plea for improve- 
ment should be accompanied by some suggestion of how to go about 
it. Reviewing, however, the history of the stage as well as motion 
picture projection it appears quite evident that no artistic advance- 
ment can come about in this new medium of expression without first 
some previous advancement in equipment. 

The statement that acting on the stage today is superior to that 
of 25 years ago has been contradicted and perhaps justly so. The 

Ihnen and Atwater — Artistic Utilization of Light 23 

thoughts of limelights along the front edge of the stage and the 
funny old painted scenery would justify saying that times have 
changed and stage effects improved. Credit for this admitted im- 
provement must go to the spotlight, arcs, and incandescent lamps. 
The spothght had made all the difference between obviously painted 
canvass fiats, and the modern scene where an illusion is created and 
a mood expressed by the color, change of intensity and direction of 
light. Figure 1 is a stage still from "The King's Children" made 
more than 20 years ago. The setting is obviously painted scenery 
and probably required exceptionally good acting. Compare this 
with the modern effect Figure 2, a convincing stage still from "Peter 

Fig. 2. — A modern stage scene. Marilyn Miller in Peter Pan — light and shade 
are employed to make this an artistic and convincing picture. 

Figure 3 illustrates the quantity of equipment required, the 
positioning of which obviously consumed considerable time. These 
are the tools with which persons responsible for the lighting have to 
work. The weight of this apparatus is terrific and requires many 
men to move it. When some of these lights are rolled over compo- 
board floors so frequently used in sets, they leave deep grooves behind 
them. It is not simply a matter of pressing a button and turning on 
the necessary lights. On the contrary it is a complicated procedure. 
In the first place the camera man, unfortunately, has to do a lot of 
thinking^ which the director already burdened with his own problems, 


Transactions of S.M.P.E., August 1925 

does not like to allow for. He has to consider the construction of the 
set, then where the action is to take place in the set. This is generally 
not in one spot but moved from one place to another. Then he has 
to consider the mood of the scene, i.e., the sort of effects that would 
emphasize the drama. In addition to these things he has to worry 
about the shape of the stars nose and sometimes the woman star is 
showing signs of a double chin — very slightly of course — he must 
eliminate the crooked nose and other touchy defects by means of 
light. He hastily forms an impression of how the set should be 
lighted and shouts instructions to the electricians who roll up their 
sleeves and start hauling great heavy cables, Figure 4, dragging them 

Fig. 3. — Photograph made immediately after a scene was completed, showing 
the quantity of cumbersome equipment employed. 

across expensive rugs and floors just varnished and waxed to look 
like hardwood. Large sunlight projectors which take a half dozen 
men to handle have to be hoisted up on platforms previously moved 
in place. 

After a few hectic hours of this, the director has about lost his 
patience and decides to shoot. He places his actors and rehearses 
them, then perhaps decides that his crossings do not work well and 
so he will just change this acting to the other side of the set. This 
will work more smoothly. That means two hours of work gone for 
nothing but what can the camera man do? The director wants to 

Ihnen and Atwater — Artistic Utilization of Light 


The camera man must divert the director's attention by fair 
means or foul until he gets time to change a spotlight or two. But 
the director cannot be stalled off long and soon yells, "camera, 
action!" The hero starts to do his stuff. 

Frequently when the rushers are viewed in the projection room 
the next morning, they may look satisfactory, but if a good painter 
happened to be there he would ask why it was that when the actor 
walked across the set a great pin wheel (Figure 5) of shadows revolved 
about his feet on the floor serving to detract attention from the 
actor. This picture was taken purposely to illustrate the pin wheel 
effect and the shadows are somewhat exaggerated. 

Fig. 4. — Coils of heavy cables with bulky connecting-blocks photographed at the 

conclusion of a small scene, indicating the considerable time involved 

in arranging the Hghting equipment and the enormous load 


The best argument for improved facilities is a consideration of 
the cost of production. Fifty percent of the time consumed in pro- 
ducing a motion picture is used in arranging the lighting and picture 
costs are based entirely on the time element. The preliminary work 
of preparing the story and final work of cutting are more or less 
fixed charges, not dependent so much on the time element. The 
terrific overhead of stars, production staff and studio makes speed 


Transactions of S.M.P.E., August 1925 

It might be well in order to understand some of the problems 
involved in lighting a set to imagine a simple example such as a 3 
wall or U shaped set approximateh^ 12 feet wide. Assume the action 
to take place ' 'up stage" near the back wall and in one corner. Assume 
there is no ceiling and naturalh^ no front. Now set up the camera and 
light up your characters and background — Easy — just put a bunch 
of broadsides each side of the camera and shoot. The result is a flat 
picture with no detail, distance or separation between actors and 
background. Each arc would cast a separate shadow on the opposite 
wall. The way to improve such a picture would be to add a couple of 

Fig. 5. — "Hard light" from spots if not carefully employed ^dll produce deep 

shadows such as these and thus cause revolving pin wheels about the 

feet of mo\^ng characters. 

spotlights overhead directed on the back wall. This might accentuate 
the floor shadow somewhat, but they are less objectionable than the 
wall shadows which with such treatment would be eliminated. The 
spots would throw enough light on the heads and shoulders of the 
characters, producing a sort of fringe of light around them and 
partially separate them from the wall. 

Figure 6 illustrates three ways of overcoming these diflSculties. 

Ihnen and Atwater — Artistic Utilization of Light 


The first way, A. would be to move the characters forward and 
put diffusers on the spothghts. This will eliminate shadows on the 
walls and floor. 

The second way, B, would be to move the characters out along 
the back wall, away from the corner and move the camera closer. 
In this picture the actors would appear only against a flat wall and 
the side walls could be eliminated. It would, however, permit moving 
lights into the set on each side of the characters. 

o -o 


neURL NO. G 



lNDICflTE.-5 CFintf^fl. 





The third way, C, would be to eliminate the overhead spots by 
cutting openings in the walls. These openings would have to be 
doors, windows or arches whether they belonged there or not. 

In other words it is necessary to balance the light from various 
directions so as to get that exact and beautiful play of light and 
shade that makes the motion picture a work of art. It is control of 
these light and dark spots that is so important. These light and 
dark spots are referred to as values and on their arrangement depends 
to a large extent the artistic quality of a picture. 

Lighting is the very essence of the motion picture. Figuratively 
it is the palette of the art director and occupies the same relation as 
pigment does to painting. It is the medium. It might be argued that 
action is the medium of the movie, but if the analogy of the painting 
is followed out, action is the subject matter expressed in terms of 
light. Light should be one of the first thoughts in visualizing a scene. 
It is just as important as the actor and, in fact, sometimes it takes the 

28 Transactions of S.M.P.E., August 1925 

place of the actor. It is often possible to heighten the dramatic value 
of a scene by suggesting the actors with a play of hght rather than 
by actually showing them. 

Up to this point "hght" has been referred to frequently, always 
as a desirable and necessary medium. Light reveals the shadow; 
darkness, or the absence of light reveals the light. 

What is seen on the screen of the theatre is a succession of 
shadows cast by the image on the film in the path of a beam of 
hght. The absence of light is exactly as important as the light. We 
do not see the light any more than we see the darkness as far as art is 
concerned. Light by itself we know, if too uniform and diffuse, can 
completely conceal the shape and contour of an object. It only 
becomes visible when shade and shadow are allowed to play on its 

Darkness generally is considered to be a negative quality but in 
art it is a positive quahty. It is physically easier to control values in 
painting than is perhaps the case in any other medium. If a dark 
tone is required, a dark pigment is used, if a light tone is wanted a 
hght pigment is used and so on. Painting with hght rays is painting 
with a more elusive quantity than oil paint. 

By going through the same mental process as required in making 
an oil painting and applying the same general principles of art, it is 
possible to decide in a particular ''shot" where the light tones ought 
to be and where the dark tones ought to be. All that remains after 
that is physically to get them there. That is the job which requires 
so much time and to which there is no formula. With this thought in 
mind it might be of interest to examine a few stills. The lighting is 
practically the same as that used for the movies. While these pictures 
should not be taken as examples of perfection they are all very well 
done and will serve for the purpose of illustration. 

Natural lighting was the aim in the following sets and where this 
was not accomphshed there was generally some mechanical or practi- 
cal reason preventing it. If these were perfect examples of lighting 
there would be no point in showing them to a group of engineers, 
unless it was for reasons of purely personal interest. The fact that 
they are pretty good, but not perfect by any means, should serve to 
stimulate interest in eliminating the difficulties involved. 

Figure 7 is a long shot of a set representing an upper chamber 
in an Enghsh tavern during the time of Cromwell in Old England. 
Note that in this room a complete ceihng was constructed, entirely 
covering the set and not allowing any overhead light. Overhead 
illumination would be the worst lighting fault that a set of this kind 
could have. The corner of the room by the pallet bed, being almost 
completely boxed in, presents a lighting problem similar to that 
described in discussing the imaginary set in the first part of this 
paper. Here it will be recalled that difficulty was experienced where 
action took place in a corner. The lighting used in this "still" (not 
the same as that used for the motion picture camera) consisted of two 

Ihnen and Atwater — Artistic Utilization of Light 



Fig. 7. — The corner of this room, with its low ceihiig, pit'^iin^ a diliuull Hghting 

problem. Note the ineffectiveness of the lantern and the inconsistency 

of its shadow on the wall. 

Fig. 8. — A well illuminated set employing camouflage lighting. The curtain 

shadows are painted, while the highlight on the shoulders of 

Mr. Barthelmess is produced by a concealed spot. 

30 Transactions of S.M.P.E., August 1925 

spotlights whose beams are quite easy to detect, and some Cooper- 
Hewitt hghts on the left side. Note the shadow of the lantern on the 
wall as well as the absence of hght on the curtain which should have 
fallen on it from the lantern. Also the line of the vertical shadow on 
the right which unnecessarily repeats the upright timbering in the 
foreground. This timbering was purposeh^ built in the foreground 
to add such a dark line. The wall on the right of the bed should have 
been all hght. 

Figure 8, is an action "still/' showing how the shadow on the 
curtain was produced bj^ means of black paint and the light below it 
b}^ white paint. High hghts on the bracket and the beam above were 
painted. The shadow under the shelf was somewhat weakened by 
too much front Hght. The light on Mr. Barthelmess, which looks as 
if it came from the lantern, was produced by a "Baby Spot" hidden 
above. The balancing light on his head came in through the open 
door. Note the shadow of the Inkeeper's head across his shoulders; 
this also comes from the "Baby Spot." The face of the lantern had 
to be frosted so that it did not become glaring and draw attention 
from the star's face. Note how the highhght on his shoulder immedi- 
ately attracts the attention, making the star's face the center of 

Figure 9 is a short shot from the "Night Life of New York" a 
Paramount picture. Note how the spotlight has been used to bring 
up each of the characters. These highlights on the heads of each of 
the two men separate them from the dark background at the same 
time revealing the position of i\Ir. Kelley's left arm. The dark coat 
of Miss Gish has been revealed in the same manner. 

Figure 10 is the same picture as Figure 9 with the highlights 
eliminated. Here the dark heads of the men disappear in the back- 
ground and there is no suggestion of the left arm position. Ob\aously 
spotlighting of this kind is necessar3^ If artisticall}^ employed as in 
Figure 9 it is most pleasing and desirable. On the other hand, this 
effect and more especially that obtained from back lighting has been 
over done in the last few years. Despite newspaper stories to the 
contrary, actors and actresses as a rule do not need artificial halos 
around their heads to make them acceptable to the public. By a 
careful study of values, backlight can often be entirely eliminating, 
to the betterment of the picture. 

Figure 11 illustrates an elaborate scene from the recent pro- 
duction "Robin Hood." Light values here have been skillfully em- 
ployed to make a well balanced composition. The dim illumination 
above accentuates the height of the scene while shadows and high- 
lights bring out depth and character. Note particularly the pleasing 
appearance of the brightly lighted doorways which apparently 
illuminated the set. 

Figure 12 is of a small set taking during rehearsal. Note how 
the lantern light on the floor was painted. The director's shadow on 
the w^U looks as though it is coming from the lantern and is good, 

Ihnen and Atwater — Artistic Utilization of Light 


Fig. 9. — Spotlighting is used in this set to separate the characters from the 
background and to accentuate the predominating features. 







^^^J ^ '^ 9^1 








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Fig. 10. — The value and necessity of highlights are appreciated when this 
illustration is compared with Figure 9. 


Transactions of S.M.P.E., August 1925 

Fig. 11. — An excellent example of artistic utilization of light revealing the 
magnitude and depth of this elaborate setting. 

Fig. 12. — The lantern hght on the floor was actually white paint, while the 
4ight on the actor and his shadow were produced by a high- 
intensity spotUght. 

Ihnen and Atwater — Artistic Utilization of Light 33 

but the actor in the corner is casting a shadow on each wall. For- 
tunately, one is much stronger than the other. The large canvas 
frame overhead was placed there to prevent any daylight from 
seeping into the set. Overhead light on this set would have been 
bad. The studio in which this picture was made is the old Universal 
studio in Fort Lee, New Jersey, which has a glass roof. 

Fig. 13. — Candlelight effect apparently produced by the taUow candle on the 

table. The actual source was a spotUght, the use of which can 

be detected by the floor shadows. 

The inference to be drawn from all these pictures of interiors 
is that when the industry has developed to the point where illumina- 
tion can come from natural sources, motion pictures will be cheaper 


Transactions of S.M.P.E., August 1925 

to make and better to look at. Firelight, light from lamps, and candles 
are all very difficult to produce. There is no kind of candles now in 
use in studios that has sufficient light to "pick-up" on the screen. 
Where^they are used near a wall a spotUght is generally thrown 
against the wall behind them, but the flame is barely visible, and if 
someone should walk in front of the spothght the candlelight would 

Fig. 14. — Imitation Firelight here was produced by a concealed arc behind the 
logs and by white paint on the back of the fireplace. 

disappear. One trick now being used for candlelight is produced by 
cutting a hollow paper candle in half lengthwise, and hiding a tiny 
arc behind it. This throws a pretty good hght behind it, with no 
light at all in front, so that the candle is silhouetted against its own 
light and, of course, has no flame. When a candle of this sort is carried, 

Ihnen and Atwater — Artistic Utilization of Light 35 

the actor has to conceal the wires in his clothes, but there is generally 
no particular disadvantage in this. 

Figure 13 — The apparent candlelight is produced from a spot- 
Hght on the left. Its use, however, can be detected by the table 
shadows. This is a picture of Xeil Hamilton in "Isn't Life Wonder- 
ful," produced b}^ United Artists. 

The firehght of Figure 14 is also artificial being produced by a 
smaU arc concealed by the logs in the hearth. 

Fig. 15. — An outdoor set in which the sun itself furnishes natural and true lights 

and shades. 

Figure 15 is a set produced out-of-doors. This was produced 
under natural daylight and is taken from "Robin Hood," a United 
Artists production. Note the crispness and transparency of the 
shadows. Such a picture could never be produced with electric 
light. It could be approached but the same values would not be 
present. By the time sufficient light had been poured into this scene 
to allow for pick-up the shadows would be entirely washed out or very 
much reduced in their values. 

Everyone has probably noticed or been annoj^d, unconsciously 
perhaps, by seeing a movie scene wherein the sunhght poured in a 
great window through radiating shadows, so that it was evident that 
the sun was only eight feet outside of the window or thirty inches in 
diameter. This fault of artificial sunlight is illustrated in Figure 16. 

In addition to the problems encountered in securing proper light 
direction there are also difficulties in controlhng the quantitj^ of 
light. One method frequently employed consists of using compo- 


Transactions of S.M.P.E., August 1925 

board screens known in the studio as "goboes." These are interposed 
between the camera and the set to block out Ught where it is not 
wanted. They are, however, cumbersome and serve to clutter up the 
studio. Shadows of any particular character or contour are obtained 
by placing screens or objects in the path of the spothght beam. Where 
tree shadows are wanted, for example, a branch of a real tree is 
brought in and nailed up in front of the lights. 

As the brilliancy of the arc lights are practically constant, 
various methods must be employed to control their light output. 
One scheme is to use an iris diaphragm shutter which screens ofif a 
certain portion of the total light output. Another method of control- 

ft ^^^A -4 t % 



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■::^^m^'' r\»s ' '' 


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Fig. 16. — Artificial sunlight is apparent because of the diverging shadows on the 


ling illumination is by use of colored filters in front of the arcs. The 
impression one immediately forms on observing these screens is that 
they are used to produce a given color, for example, pink over any 
portion of the set. Their object, however, is to control or dim the 
illumination. As each color has a different light transmission, care- 
fully selected filters permit the scene to be illuminated to almost any 
desired intensity. 

In a brief and general discussion of this character only isolated 
and individual problems can, of course, be considered. The various 
illustrations have been employed to show the possibilities of light 
in photography of better motion pictures. It is hoped that future 
developments in lighting equipment will place in the art director's 
hands a medium for a more flexible, convenient and economical con- 
trol of hght and shade which will make future productions as far 
superior to our present films, as the pictures of today are superior 
to those of only a few years ago. 


Mr. Brown: The use of white paint in fireplaces in order to 
give the effect of a brilUant source of illumination which is not 
present seems to be an extremely valuable aid to composition, and 
I think it will have a very wide application in the future. 



By L. M. Townsend* and Lloyd A. Jones** 

Communication No. 237 from the Research Laboratory of the Eastman 

Kodak Co. 

'^Coloring is the sunshine of art, that clothes ^poverty in smiles, and 
renders the prospect of barrenness itself agreeable, while it heightens the 
interest and doubles the charm of beauty." — Opie. 

THE love and appreciation of color is firmly ingrained in the human 
consciousness. Our oldest written historical records show that 
color was appreciated and used extensively by the peoples of those 
early ages. Prehistoric remains dating back centuries before the 
existence of a written language indicate that the Cro-Magnon men, 
the first true men (later Paleolithic age, approximately 20,000 B.C.) 
decorated the walls of the caverns in which they lived with colored 
paintings. Wells^ states "It greatly aids us to realize their common 
humanity that these earliest true men could draw. Both races, it 
would seen, drew astonishingly well. They were by all standards 
savages, but they were artistic savages. They drew better than any 
of their successors down to the beginnings of history. They drew 
and painted on the cliffs and cave walls that they had wrested from 

the Neanderthal men They buried their dead, often with 

ornaments, weapons, and food; they used a lot of colour in the burial, 
and evidently painted the body. From that one may infer that they 
painted their bodies during life. Paint was a big fact in their lives. 
They were inveterate painters; they used black, brown, red, yellow, 
and white pigments, and the pigments they used endure to this day 
in the caves of France and Spain. Of all modern races, none have 
shown so pictorial a disposition; the nearest approach to it has been 
among the American Indians." So from the very dawn of civiliza- 
tion color has played an important part in the lives of men. Nor 
is this to be wondered at since color is an inseparable part of vision. 
Every visual sensation carries with it its color content, and as stated 
by Hering, ''Our visual world consists essentially of differently 
presented colors : and objects as seen, that is visual objects, are nothing 
but colors of different nature and form." This fact has been recog- 
nized by many others, among them Clerk Maxwell who states, 
"All vision is color vision, for it is only by observing differences in 
color that we distinguish form." 

* Projection Engineer, Eastman Theatre and School of Music, University 
of Rochester. 

** Physicist, Research Laboratory Eastman Kodak Company. 

1 Outlines of History. McMillan Co., 1923, p. 70-71. See also "History of 
Art". Ells Faure Co. I (Ancient Art, p. 10-23). 


Towns€7id and Jones — Use of Color 39 

The human race evolving in an environment so colorful as that 
afforded by nature could not well be indifferent to the beauty and 
charm of this phenomenon. It seems only natural, therefore, that 
very early in their evolution, our prehistoric ancestors should strive 
to imitate in permanent form the transitory colors exhibited by nature. 
Ever since that remote period color has been used in almost every 
phase of human activity and the art of combining and assembling 
colors in pleasing forms has developed to a high state of perfection 
reaching its pinnacle perhaps in the works of famous painters. 

The great difference between color in nature and in the handi- 
work of the artist is that the latter is largely static, while the former 
is frequently mobile (dynamic). There is a fascination and charm 
in the ever-changing color as observed in nature which we can not 
hope to find in the static production of the artist. Many of the best 
artistic results are good because the artist has caught a fleeting color 
effect and fixed it on his canvas. If this is true, how much more 
interesting and beautiful would be a picture having a mobility of 
coloring similar to that displayed by nature. The motion picture 
has made it possible to reproduce mobility of form as characterized 
by differences in brightness (light and shade), but unfortunately, the 
photographic process in common use at the present time is not capable 
of reproducing the chromatic attributes of color, and we are forced 
to be content with pictures from which these chromatic factors are 

In many of the modern motion picture theatres the programs 
offered include other types of entertainment such as ballet, organ, 
orchestral, and vocal numbers. The use of colored Hghting effects 
in conjunction with these numbers has already been developed to 
quite an extent. There seems to be little doubt that an artistically 
arranged and carefully executed color accompaniment is very 
satisfying and enhances materially the enjoyment of other visual 
and auditory sensations. In connection with the production of such 
color accompaniments used in the Eastman Theatre some new types 
of color projecting equipment giving dynamic color effects have been 
developed and it is the object of this paper to describe their con- 
struction and use. 

The successful use of such color effects as an accompaniment 
to the orchestral, vocal, and ballet numbers, or even by themselves 
as a prelude to the feature picture, at once suggests that form of art 
which has frequently been designated as color music, but for which 
the term dynamic color or mobile color is more appropriate. 

While this paper does not purport to deal specifically with this 
subject, the authors would like to take this opportunity to express 
a few thoughts relative thereto. There seems to be no reason, a priori, 
to assume the impossibility of combining colors in certain spatial 
and temporal sequences so as to produce an emotional effect. There 
is little doubt that colors as such do possess a certain emotional value 
although the correlation is at present not very definite. There is no 

40 Transactions of S.M.P.E., August 1925 

reason to assume that there is any unique relation between the 
vibration frequencies of sound and Hght (color), and hence that there 
is a possibility of building up a color scale upon the basis of the 
frequency relations existing in the musical scale. One of the strongest 
arguments against such a correlation is the marked difference in 
type between the visual and auditory sense organs; the ear being a 
receiver of the analytical type, while the eye is synthetic. The ear 
is able to analyze the stimulus into its component parts while identical 
visual sensations (colors) may be produced by stimuli differing widely 
in frequency composition. 

Another difficulty encountered in correlating hue (wave-length 
or frequency of light vibration) with pitch (frequency of sound 
vibration) is presented by the non-spectral hues, the purples which are 
mixtures of red and blue and to which it is impossible to assign a 
dominant wave-length. If, therefore, the radiation in the visible 
region, 400 m/x toVOOmju, be considered as analogous to an octave or 
any part of an octave in music it is difficult to know just what dis- 
posal to make of these non-spectral hues without which no color 
scale can be complete. While it is possible to designate the hue of 
these red-blue mixtures by stating the dominant wave-length of the 
hue which is complementary to them, and this subterfuge has been 
resorted to by some who have attempted to correlate hue with pitch, 
the arrangement seem highly artificial. 

The contention that the failure of the human race to develop 
an art of dynamic color during its earlier periods of evolution is an 
indication that there is no possibility of such an art, is wholly un- 
warranted. The development of an art depends upon the availability 
of the necessary equipment and materials for producing the required 
physical stimuli. Satisfactory methods of producing sound were found 
relatively early in the evolution of the race, and the development 
of the physical sciences was such as to provide adequate means for 
building up the art of music. Moreover, each individual was endowed 
with a pair of vocal cords which at least in some cases, were adequate 
for the production of musical sounds, although it is unsafe to generalize 
too far in this direction. 

While colored media (pigments, dyes, colored glass, etc.) were 
discovered and used very early in the history of the race, these afford 
a means of producing static effects only. Adequate means for the 
production of dynamic effects became available only when methods 
of producing light artificially in appreciable quantity were developed, 
and this accomplishment of science is of very recent date. Previous 
to the discovery of electricity the human race was dependent for 
artificial light upon very primitive and inadequate methods. It is 
rather hard to realize that it is only within the last fifty, or at most 
one hundred years, that the human race has had available means of 
producing artificial light in any appreciable quantity. The electric 
arc was invented by Sir Humphrey Davy in 1800. The first in- 
candescent lamp was made by Edison in 1879 and these were produced 

Townsend and Jones — Use of Color 41 

commercially for the first time in 1881. Artificial light is, therefore, 
a relatively new tool in the hands of man, and it is little wonder 
that he has not as yet completely mastered all of its possible uses, 
nor under such conditions is it remarkable that an art of dynamic 
color did not evolve along with the art of music. Nor is it reasonable 
to expect that a finished art can grow to maturity in a short time, 
for not only must the fundamental laws be discovered, but the ap- 
preciation of such an art is something which must develop gradually 
by a process of evolution similar to the way in which appreciation 
of music has developed during the past five or ten thousand years. 

There have been many efforts, within relatively recent times, 
to develop an art of dynamic color. In many cases this effort has not 
been well directed and attempts have been made to establish a 
specific connection between music and the art of dynamic color. 
There is little doubt that such an effort is vain, and we feel that if 
an art of dynamic color is to be developed it must stand on its own 
merits as a means of artistic or emotional expression entirely in- 
dependent of the art of music. 

Among the attempts that have been made to develop dynamic 
color art may be mentioned that of Scriabine^ in which a color score 
was played along with the musical production of Prometheus. The 
work of Mary Hollock Greenwolt^ is also worthy of note, and more 
recently Wilfred^ has developed an instrument, termed by him the 
clavilux, which is played in a manner similar to the organ and project 
on the screen many form of changing color. At best only a small 
beginning has been made, and very much fundamental research work 
must be done before anything like a finished art can be expected. 
The increasing attention that is being given to the use of color effects, 
both static and dynamic in many different fields, indicates a growing 
appreciation of color in its more abstract forms. This paper makes 
no pretense of contributing to the theory of the art, but it is thought 
that the duplex projector using pattern plates of complementary 
types and compound wedge filters of variable color is a useful addi- 
tion to the rapidly increasing number of tools available for use in the 
development of this art. 

Color Nomenclature — The terminology of color is at present in a 
rather chaotic condition, an entirely different meaning frequently 
being attached to the same word by different individuals. This 
condition, since it results in misunderstanding and confusion, is 
undoubtedly one of the causes of retarded progress. Recently the 
committee working under the auspices of the Optical Society of 
America has attempted to construct a rational terminology. In their 

2 The Harmonies of Scriabine, London Musical Times, March, 1913, p. 157. 

3 Mary Halloch Greenwolt, Trans. Illuminating Engineering Society, 
Vol. 16 (1921), p. 110. 

* Wilfred, Trans. Illuminating Engineering Society, Vol. 17 (1922), p. 8. 

42 Transactions of S.M.P.E., August 1926 

report^ definitions for many of the words used in this field are proposed. 
We wish to recommend strongly that this report be given careful 
consideration by all of those interested in the subject of color and its 
application. Definitions of some of the more important terms as 
proposed in the report mentioned are quoted below, and an attempt 
has been made in this paper to adhere as closely as possible to this 

Color — "The general name for all sensations arising from the 
activities of the retina of the eye and its attached nervous mechan- 
isms, this activity being in nearly every case in the normal individual 
a specific response to radiant energy of certain wave-lengths and 
intensity. It may be exemplified by enumeration of characteristic 
instances such as red, yellow, blue, black, white, gray, etc." 

It will be noted that according to this definition black, white, 
and grays are included as colors. While there is some objection to 
this it seems on the whole more satisfactory than the opposite course. 

The word color is used at present in two distinctly different 
senses, the one including the gray series, the other excluding them. 
The extend of usage, so far as can be determined, is about equal 
for the two meanings. This double usage is obviously undesirable. 
If the above definition is adopted it will be necessary to use another 
term to replace the use of color in the hmited sense. 

Chromatic colors — This term is proposed for use in the place of 
the present limited usage of the word color, and is the general designa- 
tion for all colors possessing the hue attribute. 

Achromatic colors — This term may then be used to designate 
all colors from which the hue attribute is absent, that is the grays, 
black, and white. 

Color of an object — As stated above color is defined specifically 
as a sensation. When the word is used in designating the char- 
acteristic of an object it must be kept in mind that it is understood 
to indicate the sensation produced by the radiation reflected (trans- 
mitted or emitted) from the object, and for the sake of definiteness 
this usage should further be limited to the condition that the object 
is illuminated by white light. 

Color of light — Likewise this usage of the word refers to the sensa- 
tion produced when the radiation in question falls upon the retina, 
or since this characteristic of light is in practice usually judged by the 
appearance of objects illuminated thereby, this term should be under- 
stood to refer to the sensation produced by the light when reflected 
from a nonselective, white or gray, surface. 

White light — This concept is of fundamental importance for 
many purposes such as the definition of complementaries and the 
establishment of the laws of color mixture. In its broadest sense 
the term must apply to radiation of any spectral composition which 

^ Report of Committee on Colorimetry for 1920-21, J. Optical Society of 
America; Vol. 6, 1922, p. 527. 

Townsend and Jones — Use of Color 43 

will excite a hueless or gray sensation. Since the eye is synthetic in 
action, the gray sensation may be excited by an infinite number of 
different spectral energy compositions. For purposes of standardiza- 
tion it is desirable to limit the application of this term to one particu- 
lar type of distribution. From the standpoint of evolution it seems 
most rational to consider the radiation from the noonday sun as the 
adequate stimulus for that sensation which we term white. Since 
the spectral distribution of this radiation can be almost perfectly 
matched by a complete radiator operated at a color temperature of 
approximately 5200° K such radiation may be specified as standard 

The nature of color, i. e. the sensation produced when radiant 
energy falls upon the retina, can be completely specified in terms of 
three fundamental attributes: 

(a) Brilliance 

(b) Hue 

(c) Saturation 

(a) "Brilliance is that attribute of any color in respect of which 
it may be classed as equivalent to some member of a series of grays 
ranging between black and white." 

(b) "Hue is that attribute of certain colors in respect of which 
they differ characteristically from the gray of the same brilliance 
and which permits them to be classed as reddish, yellowish, greenish, 
or bluish." 

(c) "Saturation is that attribute of all colors possessing a hue 
which determines their degree of difference from a gray of the same 

The color of any object as seen by the eye is in general dependent 
upon two factors : 

(a) The absorbing, or in the case of self luminous bodies the 
emitting, characteristics of the object. Since the great majority of 
natural objects are nonluminous, it is the selective absorption that is 
of interest in most cases. 

(b) The quality, or spectral composition of the incident radiation. 
Character of the receiving surface — Since this paper deals with a 

method of producing colored effects by projection of light onto a 
surface it will simplify the discussion somewhat to eliminate, as far 
as possible, the influence of the surface itself. It will therefore be 
assurned that the surface (screen, curtain, drop, etc.) onto which 
the light is projected is non-selective, that is white or gray. As a 
matter of fact such a surface is in general most satisfactory for prac- 
tical purposes. A surface having marked selective absorption tends 
to limit the range of hues that can be obtained. For instance, a yellow 
surface, absorbing the radiation of shorter wave-lengths which evoke 
the blue sensation, does not reflect blue light, and hence if blue light 
be projected thereon the surface will appear black. Selectively 
absorbing curtains or screens may, however, be very useful in special 

44 Transactions of S.M.P.E., August 1925 

cases in the production of a composition from which it is necessary 
or desirable to exclude certain hues or to enhance certain hues. 

Character of the light source — The spectral composition of the 
radiation emitted by various artificial sources differs enormously. 
For practical purposes, however, only the electric arc of some type 
and the incandescent lamp need be considered. The high efficiency 
tungsten incandescent lamp operates at a color temperature of ap- 
proximately 3000° K, while the color temperature of the crater of 
the ordinary carbon arc may be taken as approximately 4000° K. 
In the case of the modern high intensity arcs, crater temperatures 
as high as 5000° K or even greater are obtained. It is evident, there- 
fore, that the color of the arc approaches that of our previously 
defined standard white. The tungsten lamp, however, is appreciably 
lower in temperature and if compared directly with standard white 
appears appreciably yellowish. However, for practical purposes of 
projection and the production of color effects, all of the sources men- 
tioned may be considered as approximately white. The deficiency 
of the shorter wave-lengths is sometimes a serious disadvantage 
(especially in the case of the tungsten source) when it is desired to 
obtain blues and violets of great brilliance and saturation. A non- 
selectively reflecting surface illuminated with light from any of the 
sources mentioned above will appear white provided no standard of 
comparison is present and the term white light is frequently used 
loosely as designating any radiation in which all wave-lengths within 
the visible region, 400 m^ to 700 m/x, are present in relative propor- 
tions markedly different from those of a complete radiator at 5000° K. 
In the production of color effects by projection of light it is desirable 
that the equipment shall be capable of projecting light of any desired 
color. Assuming that the source used is emitting radiation of all 
wave-lengths within the visible region, the light falling upon the 
receiving surface can be modified to any desired color by placing 
between the source and the surface a transmitting material (glass 
gelatine, etc.) having the proper selective absorption. This absorbs 
or subtracts certain wave-lengths and permits other wave-lengths 
to pass through entirely or partially unimpeded and the color thus 
produced is said to be obtained by a suhtractive method. Anj^ desired 
color can be obtained in this way, and with a sufficient number of 
sources and filters one source could be used for producing each desired 
color. When we consider, however, that there are approximately 125 
perceptibly different hues (including the nonspectral purples); 20 
perceptible saturation steps between zero and one hundred per cent 
saturation; and at least one hundred brilliance steps, making it pos- 
sible to produce 250,000 different colors, the absurdity of using one 
source for each color is at once apparent. 

Color mixture — It is necessary, therefore, to adopt a method 
whereby the required colors can be obtained by the mixture of a 
relatively few components. There are two ways in which color mixing 
may. bB accomplished. These methods are usually designated as 

Townsend and Jones — Use of Color 45 

additive and suhtr active. When pigments or dyes are mixed together 
in order to form some other color the resultant effect depends upon 
the laws of subtractive color mixture. When two lights of different 
colors are projected on the same area of a screen thus producing a 
third color, the result depends upon the laws of additive mixture. 
It should not be understood by this that the laws governing color 
mixture in the case of light and pigments are in any way different; 
the sam'e fundamental rules apply and depend only upon the manner 
in which the mixture is made. 

AMitive mixture — It has been found that all possible colors can 
be produced by methods of additive mixture when three colors which 
are termed the additive primaries are used. These are red, green, 
and blue. The mixture of red and green in this way gives yellow, 
green with blue gives blue green, and red with blue gives magenta 
or purple. By varying the proportions in which these three primaries 
are mixed, any desired hue can be obtaioed. In order to build up 
color in this way for use in the theatre it is necessary to have three 
light sources in front of which are placed the three additive primaries 
in the form of filters. By controlling the intensity of each source 
any desired color can be produced on the screen. 

Subtractive mixture — The subtractive primaries are magenta 
(minus green), yellow (minus blue), and blue green (minus red). 
In order to produce a desired color on the screen filters of the three 
subtractive primaries are used with a single light source. The minus 
red used with the minus blue gives green, minus blue with minus 
green gives red, and minus green with minus red gives blue, and by 
controlling the thickness or density of the three filters any inter- 
mediate hue can be obtained. 

Thus by using either the three-color additive, or the three-color 
subtractive method it is possible to obtain any desired color. In 
practical work, however, it is rather inconvenient to use three in- 
dependent sources and for this reason the three-color additive system 
is not very generally employed. The use of two independent light 
sources, however, is not open to so great objection and it has proven 
fairly easy to utilize a two-color additive method. This combined 
with the three-color subtractive method offers a possibility of pro- 
ducing a very wide range of color effects. 

The method devised for producing dynamic color effects with 
this combination of a two-color additive with three-color subtractive 
is illustrated by Fig. 1. The apparatus consists essentially of two 
projectors of the stereopticon type mounted together and so adjusted 
that they will project two slides in register on the screen. The optical 
arrangement is shown schematically in the figure. Si and S2 represent- 
ing the light sources, Ci and C2 the condenser lenses, Pi and P2 the 
object slides, Li and L2 the projecting lenses, and R the screen on 
which the image is formed as indicated at MN. For producing these 
color effects slides or object plates of two different types are used. 
Slides which are complementary to each other in both form and 


Transactions of S.M.P.E., August 1925 

Townsend and Jones — Use of Color 47 

density are used in both cases, but in type A only two densities, one 
very high and the other very low, are present on each slide. Thus 
No. 1 of type A, which may be referred to as the positive member 
of the pair, consists of an opaque arrow on a transparent background; 
while No. 2 of this type, which may be referred to as the negative 
member, consists of the same pattern in which the arrow is trans- 
parent and the background opaque. Slides of type B are made up 
of more than two densities. This is illustrated in the figure; in No. 1 
of type B, which again may be referred to as the positive member, the 
inner rectangle varies continuously in density from one end to the 
other. This is on a background which also varies continuously in 
density, but in the opposite direction to that of the small interior 
rectangle. The other member of this pair, the negative member 
shown as No. 2 of type B, is the exact complement of No. 1 in both 
form and density, and if superposed upon No. 1 would produce equal- 
ity of density over the entire area. Now let us assume that the light 
sources in the double projector are so adjusted that the screen bright- 
ness due to source Si is exactly equal to the screen brightness due to 
the source S2. Now if the slides shown as type A in the figure be placed 
in the double projector and projected in perfect register on the screen 
R, the field will be uniformly illuminated and the pattern will be 
invisible. If a filter is placed as indicated at Fi a part of the light will 
be absorbed, the balance on the screen will be disturbed and the 
pattern will be visible. Assuming that No. 1 of the pair is placed in 
the upper projecting system, any filter placed in the position indicated 
will decrease the screen brightness corresponding to the background 
area (the transparent portion of slide No. 1) and hence the back- 
ground will be less bright than the arrow. If the filter Fi absorbed 
selectively, the background will then be colored. Now if a filter F2 be 
placed in a lower beam having a. different selective absorption the 
arrow will appear of one color while the background will have a dif- 
ferent color. In this way a design in two colors can be formed on the 
screen. The entire background will be uniform in color and the arrow 
or design also uniform in color. Slides of type B give a somewhat 
different result when these are placed in the double projector and 
projected in register with no filters in position and with the sources 
balanced in intensity, a screen uniform in brightness is again obtained 
and the pattern is invisible. If filters of different colors be placed in 
the two beams the pattern becomes visible. The small rectangle will 
now vary in color from one end to the other, one end being the color 
as given by the filter Fi, and the other end of the color given by F2. 
Between the extremities a graded color effect is obtained depending 
upon the characteristics of the filters Fi and F2. The same is true of 
the background area except that the color radient is in the opposite 
direction than that of the small rectangle. The variation in color 
within the small rectangle is built up by the mixture of color according 
to the additive principle and the color sequence obtained will depend 
upon the filters used. Slides for use in this manner are made photo- 


Transactions of S.M.P.E., August 1925 








Townsend and Jones — Use of Color 


graphically, one being negative and the other a positive printed by 
contact therefrom. To obtain perfect balance it is necessary that 
the negative and positive be carefully matched with regard to density. 
This condition of balance is fulfilled if the two slides when placed in 
superposition give a uniform density over the entire aiv^a. As a matter 
of fact, for practical purposes it is not essential that perfect balance 
be obtained and it is only necessary to fulfill this condition when it is 
desirable that the pattern be made invisible on the screen at certain 

Blue" Green 




Vel low 


Fig. 3 — Diagram showing color distribution in compound filter. 
Sector filter made up of color gelatines. 

points in the cycle of color change. With stationary filters placed at 
Fi and F2 the color effect is static and in order to introduce mobility 
it is necessary to use at Fi and F2 filters which vary from point to 
point and which can be moved in order to produce a change in the 
colors on the screen. This is accomplished by use of a compound 
filter built up of three elements as shown in Fig. 2. For this purpose 
the subtractive primaries are used and the filters are made in the form 

50 Transactions of S.M.P.E., August 1925 

of disc wedges. For instance, the disc A is a minus red (blue green) 
filter so made that it is effectively of zero thickness at the point a, 
increasing to a maximum thickness at the opposite end of the diam- 
eter. The variation in saturation along the diameter is indicated by 
the wedge at the right of the circle. B and C indicate the disc wedges 
of minus green and minus blue respectively. The compound filter is 
then made up by superposing these three as indicated at E and F. 
In assembling the elements the points a, 5, and c are disposed as 
indicated by the figure and in the finished filters lie at points equally 
spaced about the circle. These compound filters are then placed in 
front of the projectors as indicated in Fig. 1, the optical axes passing 
through the filters at the points indicated as P and O. The compound 
filter produced in this way gives a result as illustrated by the diagram 
in Fig. 3. Since the thickness of the minus red wedge is zero at point 
a, it follows that a red filter will be produced at point a, and likewise 
green will lie at point 6, and blue at point c, while in between these 
points will be found yellow, blue-green, and magenta. All possible 
hues are therefore found arranged around the periphery of this disc. 
If the three components of the compound filter are properly balanced 
with respect to each other, a nonselective area (neutral) will be found 
at the center of the compound filter. Saturation, therefore, varies 
along the radius from zero at the center to the maximum at the peri- 
phery. It will be noted that complementary colors are found at the 
opposite ends of any diameter and hence with such compound disc 
filters are mounted as indicated in Fig. 1, the background color on the 
screen must be complementary to the color of the pattern. If both 
discs are then rotated in the same direction and at equal angular 
velocities this complementary relation must persist, while the hue 
changes through every possible value during one revolution of the 
filter. In this way, using slides of type A a pattern of one color on a 
background of its complementary can be obtained, and by rotating 
the disc filter every possible combination of complementaries can be 

By using slides of type B more complex effects are produced and 
in this case we have on the screen at any instant the complete series 
of colors which can be produced by additive mixture of the color of 
two filters in all possible proportions. Thus if the compound filters E 
and F as shown in Fig. 2 be so positioned in front of the projector 
that blue-green and its complement red are used, the entire series of 
colors producible by the additive mixture^ of blue green and red will 
be produced on the screen. This particular series consists of blue 
green at one end shading through a series of greens of decreasing 
saturation until at the midpoint a gray is obtained. After passing 
the midpoint a series of reds of increasing saturation will be found 
until at the extreme end the full saturation of the filter itself will 
give a red of high saturation. 

^ Color Analyses of Two Component Mixtures, L. A. Jones, Physical 
Review, N. S., Vol. IV, No. 5, Nov. 1914. 

Townsend and Jones — Use of Color 51 

By moving the two compound disc filters so that the optical 
axes pass through points nearer to the center, the saturation factor 
is decreased until at the center a gray is obtained. In this way any 
hue of any desired saturation can be obtained. The hue series obtain- 
able by the additive mixture of any pair of complementaries is limited, 
so, if it is desired to obtain a greater variety of hue, it is only neces- 
sary to shift one of the compound disc filters relative to the other. 
For instance, if the filter F be rotated through 60 degrees from its 
position as indicated in Fig. 2, the point is the optical axis of the 
lower projector and will now fall either on the diameter c or b. As- 
suming that the rotation is in the clockwise direction, this will be on 
the diameter c and at a point on the filter which is blue. The upper 
filter E having retained its position as indicated, will still be acting as 
a red filter. Under these conditions proj-ection will occur through a 
pair of additive primaries and the hue series obtainable is entirely 
different than in the case of a pair of complementaries. Using any 
pair of additive primaries for additive mixture the entire series of 
hues lying between the two filters can be obtained in almost constant 
saturation. Thus for the red and blue filters mentioned above this 
series will be limited at one end by red, run through the entire range 
of purples (red blue mixtures), and end at blue. With the disc filters 
set in this relation to each other synchronous rotation will give a 
changing series of additive mixtures. 

The most fascinating effects are produced by rotating the two 
filters rather slowly and this is best accomplished by driving them 
with a small motor through a speed reducing mechanism. The descrip- 
tion of the use of this apparatus thus far assumes that the three 
elements (A, B, and C of Fig. 2) are assembled in a fixed position 
relative to each other as indicated by the diagram E. Very different 
series of color changes can be produced by mounting each of the 
components A, B, and C separately so each can be rotated independ- 
ently of the other. By means of a suitable mechanism each of these 
elements can be driven at a different angular velocity. In this way a 
compound filter which is continually changing can be produced. The 
sequences of color obtainable in this manner are practically unlimited. 
No attempt will be made to discuss these in detail as it is quite evident 
that this general scheme can be used in many ways. Complementary 
slides made by photographing designs of various types produce, when 
projected on a suitable curtain, very beautiful effects. 

The color and design composition should receive careful con- 
sideration from the standpoint of its appropriateness to the music 
or other number which it is to accompany, or to the picture which it 
is to introduce. 

Dynamic color effects produced with this apparatus have been 
used with considerable success during the musical prelude or with 
orchestral numbers. The most satisfactory results have been obtained 
by projecting these on to a curtain hanging in vertical folds, not a 
perfectly flat surface. 


Transactions of S.M.P.E., August 1925 

Very satisfactory results can be obtained by using a filter of the 
sector type by using colored gelatines or glasses assembled as shown 
in Fig. 4. It is possible to obtain a fairly good series of colors in dyed 
gelatines and by choosing, let us say 12 filters having hues spaced 
uniformly throughout the spectrum and also through the nonspectral 





























Fig. 4^ — Illustration of a pair of pattern plates complementarj'^ in form and 
density, of the line type. 

region, the purples, a fairly good approximation to the compound 
wedge filters shown in Fig. 2, can be obtained. In this case, however, 
no variation in saturation from center to periphery will be obtainable. 
Such a sector filter mounted close to the projection lens will, when 
rotated, produce a color change which occurs in a more or less dis- 
continuous series. The transition, of course, is not very abrupt since 
when the dividing line between two filters is directly in front of the 
lens, a part of the beam is passing through each of two adjacent 
filters an additive mixture of the two filter colors is obtained. As a 

Townsend and Jones — Use of Color 53 

Fig. 5 — Illustrations of a pair of pattern plates complementary in form and 
density, half-tone type. 

54 Transactions of S.M.P.E., August 1925 

matter of fact such sector filters have proven quite satisfactory in 

By making compound wedge filters of a size just sufficient to 
cover the pattern plate, and placing them near to the pattern plates, 
that is in the focal plane of the projection lens, each projector covers 
the screen with a variable color. When these are used with pattern 
plates, as described previously, very fascinating effects are obtained. 
By properly setting the orientation of the two compound filters 
relative to each other, form elements immediately adjacent to each 
other may be projected in complementary colors, and this com- 
plementary relation will persist approximately at every point on 
the screen, but the actual hues and saturations will be variable from 
point to point. 

Further variation may be produced by flooding the entire screen 
on which the patterns are projected with colored light from a third 
independent source, such as the usual type of flood light equipped 
with gelatine or glass color filter. The possibility of using colored 
screens on which to project the patterns has been mentioned pre- 
viously and in some cases has proven very effective. 

From a careful observation of the dynamic color effects produced 
by the methods described above we have concluded that their chief 
fascination lies in the continual change of form and color. Such effects 
seem to produce a sustained interest which is markedly greater than 
that which can be obtained with a static composition. 

The type of designs which have been used successfully with 
this duplex method of projecting may be illustrated more definitely 
by Figs. 5 and 6. Fig. 5 represents a pair of design plates which are 
complementary to each other in form and in which half-tones are 
absent. Assuming that No. 1 of this pair is placed in the upper 
lantern (Fig. 1) with a red filter at Fi the light areas of this design 
will be shown on the screen in red. Now with the other member 
of the pair No. 2 placed in the lower lantern and, let us say, a blue- 
green filter at F2, the light areas of this will be shown on the screen 
in blue-green. By using a filter of variable hue on each projector 
the background and design can now be made to pass through any 
desired cycle of hue changes. 

In Fig. 6 the design plates shown represent a pair which are 
complementary in form, but differ from those shown in Fig. 5 
in that the design is composed to a certain extent of half-tones. 
With this pair the design will be reproduced in more than two hues 
since the additive projection of those areas represented by half- 
tones will result in colors built up according to the laws of additive 
color mixture. 

By projecting two such design plates slightly out of register with 
each other a marked impression of plasticity can be produced and in 
some cases it has been found that more pleasing and satisfactory 
results are obtained in this way. 

Townsend and Jones — Use of Color 







Fig. 6 — Diagram showing optical system in improved stereopticon spot and 
stereopticon flood projectors. 

56 Transactions of S.M.P.E., August 1925 

Improved spot and flood lights — The usual form of flood light and 
spot light consists of an electric arc in front of which is placed a 
single plano-convex condenser. The size of the spot or the area 
covered by the flood is governed by the focal length of the condenser 
lens and the distance between the arc and condenser. Sheets of 
colored gelatine are used to modify the color of the light as occasion 
demands. The desirability of keeping something of interest before the 
eyes of the audience at all times, even while the curtains are closed 
between different numbers of the motion picture program, has led 
to the improvement of this type of projector and the construction 
of a somewhat more elaborate form. 

We have chosen to designate these improved spot and flood 
light units as stereopticon spot lights and stereopticon flood lights. 
While there is nothing essentially new in the principle involved in 
these units they do give results that can not be obtained with the 
ordinary type of spot and flood light units, and have been found to 
fill a real need in the motion picture theatre. They have been used 
extensively in the Eastman Theatre with excellent results. The 
additional elements which must be added to the ordinary spot and 
flood are very simple and can be placed in position or removed in a 
short time. 

The arrangement of the component parts is shown diagram- 
matically in Fig. 7. To the usual flood or spot light unit has been 
added an optical bed which is a metallic bar fixed rigidly to the 
housing of the spot light and providing a means whereby additional 
lenses, iris diaphragms, etc., can be supported in alignment with the 
optical axis of the spot light. On this optical bed, 0, are mounted 
two front standards, FSi and FS2. On FSi are mounted an iris dia- 
phragm, I2, a color wheel, CW, and a slot, S4, suitable for holding 
color filters. On FS2 are mounted an iris diaphragm, I3, and an ob- 
jective lens, L. In addition to the usual plano-convex condenser, Ci, 
is added a second plano-convex lens, C2, making a complete stereop- 
ticon with condensing lenses 8 inches in diameter, three iris dia- 
phragms, Ii, I2, and I3, a color wheel at CW, slots for holding frames 
carrying color filters at Si, S2, and S4, and a slot for holding slides 
or pattern plates at S3. 

For use as an ordinary spot light the condenser C2 is removed 
and a condenser of 18 inches focal length and 8 inches in diameter 
is placed at Ci, the front standards being removed. For use as an 
ordinary flood light, the condenser at Ci is changed to one of 13 inches 
focal length and 8 inches in diameter. 

The stereopticon spot light — For use as a stereopticon spot light 
a condenser of 13 inches focal length is placed at Ci, and one of 18 
inches focal length at C2. The front standards 1 and 2 are placed 
in position and the arc adjusted at such a distance from the con- 
densers as to form an image of the arc crater on the iris I2. The 
opening in the iris I2 is focused on the stage or object by the lens L. 
The best results are probably obtained when the focus is not too 

Townsend and Jones — Use of Color 




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58 Transactions of S.M.P.E., August 1925 

sharp, or in other words when the iris is slightly out of focus. The 
size of spot is governed by opening or closing I2. The advantage of 
this type of spot is the elimination of all objectional reflections from 
the negative carbon tip, and the ability to obtain a perfectly round 
spot regardless of whether or not the crater is burning perfectly. 
If designed for special effects a diaphragm stop of any particular 
shape or design may be placed at S4, such as triangles, squares, 
oblongs, or even a shamrock for St. Patrick's day. 

The Stereopticon flood light — When using this instrument as a 
stereopticon flood light the lens L is so adjusted that it will image 
a slide placed in slot S3 upon the screen or curtain. The arc is then 
moved to such a position that an image of the crater is formed ap- 
proximately upon the lens L. The iris I2 is fully opened so that the 
beam may pass through unobstructed. The slides or pattern plates 
yvhich. will be described later are placed in the slot S3. The front 
standard, FSi, is moved to a position much nearer to the iris Ii 
than is shown in the figure and the iris I2 being out of the focal 
plane, S3 will be imaged on the curtain very much out of focus and 
may be used for producing soft blended effects. The iris I3 is suffi- 
ciently far away from the crater image so that an out-of-focus image 
of this is also formed on the screen and this too may be used for 
limiting the size of the area covered, and by using two or three of 
these lanterns together areas of different sizes arranged concentric- 
ally or eccentrically may be illuminated. 

The color wheel, CW, consists of 18 sectors made up of dyed 
gelatines chosen so as to represent the entire series of spectral and 
nonspectral (purples) hues. The projection room at the Eastman 
Theatre is equipped with 5 projectors of this type. We have been 
able to obtain good illumination over the entire stage opening, which 
is 50 feet wide, by using an ordinary arc drawing a current of 60 
amperes. The projection distance is 160 feet. 

Methods of using stereopticon flood lights — A slide of the same 
size as the color frames (9J^ x lOJ^ inches) is cut from sheet metal. 
An opening, approximately 43^ x 5^/^ inches, to conform to the 
shape of the stage opening is cut in this. The mask thus formed is 
placed in the slot S3 and focused on the stage curtains or hangings. 
If a sharp outline is objectionable this can be avoided by throwing 
the image sufficiently out of focus to suit the individual taste or 
condition. Color frames carrying dyed gelatines are placed in slot 
Si or S2 or both. By using four of these flood lights simultaneously 
with the diaphragms, Ii, on each open to different extents, and using 
four shades of one color an effect similar to that shown in Fig. 8 
is obtained. The central area is illuminated by light from all four 
spots. The zone immediately surrounding this is illuminated by light 
from three spots, the next zone by light from two of these projectors, 
and the other zone by light from only one. The central portion is 
therefore, brilliantly illuminated, while each consecutive surrounding 
zone decreases in brightness. Obviously a great many variations of 

Townsend and Jones — Use of Color 


60 Transactions of S.M.P.E., August 1925 

this effect can be obtained by using two, three, or four different colors 
in the different projectors. 

An altogether different and probably more pleasing effect can 
be obtained by leaving the iris Ii of each projector wide open and 
opening the iris I3 on each lamp to different extents. This iris is of 
course out of the focal plane of the projection lens, L, and hence a 
pleasing blending of one or more colors from light to dark without 
the appearance of sharp outlines will be obtained. A practically 
unlimited variety of color blending may be produced by the two ar- 
rangements mentioned above, or by using them in combination with 
the iris diaphragms at different positions and open to different extents. 

Another effective method of producing blended color effects is to 
place small color frames consisting of two or more parts or sections of 
different color in slot S4 which is not in the focal plane. 

Another method of using the stereopticon flood is to introduce 
slides or pattern plates in the focal plane, S3. It is impossible to use 
glass slides for this purpose on account of breakage by over-heating. 
It was found possible to reduce the heat to some extent by using 
A. C. negative carbons as positives. These special carbons contain 
a small proportion of the materials used in the high intensity carbons 
and produce a white flame arc similar to the high intensity arc, and 
is exceptionally good for the projection of color. It is somewhat 
whiter than the ordinary arc but not as bluish as the high intensity 
arc. Slides were made on 5 x 7 sheets of Cine Positive film coated 
on cellulose acetate base. These were mounted on sheet metal frames 
of the same size as the color frames in which were cut openings of 
proper shape and size to cover the stage, in the same manner as for 
use with the plain flood light. Slides made in this way have been 
applied as follows: 

(a) A slide carrying a title of a picture, or a strong scene or 
incident from the picture itself, or any scene which will indicate the 
type or locale of the number to follow may be projected over the full 
stage opening previous to starting and continuing through the in- 
troduction and title of the picture number. The intent of this is to 
assist in the creation of an atmosphere in keeping with the picture. 
Such a slide can be photographed in black and white and projected 
in two colors by using a light (high transmission) filter over the slide, 
and projecting from a second stereopticon flood a different color of 
lower brightness over the entire curtain or screen . This is illustrated 
by Fig. 9 which was projected onto the curtains previous to the 
presentation of "The Sea Hawk." 

(b) A further modification of this idea is to project, by means 
of a third stereopticon, a photograph of the star in the picture to 
follow, the size being adjusted so that it fits within the blended borders 
produced on the curtains by the stereopticon fiood light units and also 
fits nicely upon the projection screen when the curtains are parted. 
The blended border may be colored or in black and white ; the latter 

Townsend and Jones — Use of Color 






Transactions of S.M.P.E., August 1925 

Townsend and Janes — Use of Color 


Fig. 11 — Illustrating the separation of a design into two parts each being pro- 
jected wdth light of different color, and the complete design obtained by 
superposition of the two elements. 


Transactions of S.M.P.E., August 1925 

Fig. 12 — Illustration of slides made by the two-color process. 

Townsend and Jones — Use of Color 65 

effect has been used frequently with marked success. In Fig. 10 this 
idea is illustrated. 

(c) A somewhat different method of obtaining a wider variety 
of colors, while at the same time using a black and white design, is 
to make two separate slides of the same design placing a part design 
on one slide and the remainder on the other. The two may then be 
projected in superposition from two stereopticons using filters of 
different colors, using a third projector to flood the entire picture 
with a third color. This idea is illustrated by Fig. 11. One slide is 
made as shown at A and placed in one stereopticon with a red filter. 
The other slide is made as shown at B and is placed in the other lantern 
with a yellow or orange filter. The cat-tails and three butterflies are, 
therefore, shown in orange while the six butterflies on slide A appear 
as yellow. The two when projected in register on the curtain produce 
the complete design as shown at C with the red and yellow butter- 
flies intermingled. By using this idea with filters of variable hue 
in the two projectors the colors can be changed independently through 
any desired cycle. 

(d) The usual methods of two- and three-color additive pro- 
jection may also be utihzed. Thus colored pictures or designs may be 
photographed on panchromatic plates using a suitable pair of two- 
color taking filters. Positives made on acetate base from the negatives 
thus obtained, when projected in register through suitable two-color 
additive projection filters (orange-red, and blue-green) give pleasing 
results. A pair of positives made in this wa}^ and suitable for produc- 
tion of two-color additive effects are illustrated in Fig. 12. 

(e) Further variation in the effect may be obtained by using 
the same slides with filters other than the usual two-color projection 
filters, or by flooding the curtain with a third color. Using three 
projectors, the three-color additive process of producing color effects 
may also be emploj^ed. It is not necessary, for the production of these 
color effects that true color rendering be obtained, and frequently 
the most pleasing result follows rather unfaithful color reproduc- 
tions of the original. As stated previously, for three-color additive 
projection, the filters should be red, green, and blue-violet. 

In closing we wnsh to thank Mr. Norman Edwards, art director 
of the Eastman Theatre for his valuable suggestions and advice 
relative to the artistic phase of this work, and also iMr. William 
Hennesy of the Eastman Theatre who has been of great assistance 
in gathering and producing suitable designs. 

May, 1925. 


Mr. Richardson: I desire to direct the attention of motion 
picture projectionists to the new compUcations and possibiUties 
which are constantly cropping up in connection with their work. 
They must study their job or they will find themselves without one 
insofar as motion picture projection is concerned. Such things as 
have just been shown us are coming and projectionists will have to 
handle them and be able to assist in the intelligent selection of 
color and design combinations. 

Dr. Gage: When my father and I were working up a book on 
optical projection, we found many references to work — more in Eng- 
land than here — where spectacular effects were obtained by the use 
of dissolving lanterns. They were not used merely to change from 
one unrelated slide to another but one picture is dissolved into another 
similar picture, as for instance a sununer and a winter scene of the 
same landscape. In another spectacular exhibit, a projector was 
mounted on a wheeled cart behind the screen so that the whole pro- 
jector was pushed up to the screen, the slide changed, and the pro- 
jector pulled back. This whole art can be revived for use in con- 
junction with motion pictures for producing spectacular effects, and 
we have just seen a demonstration of this. 

Dr. Mees: I might point out that the slides with the floodlight 
on them give an effect exactly equivalent to a tinted film, and it is 
much better and easier to use a floodlight than to tint the film in 
most cases. You can get more varied results, there is not the danger 
of damaging the film by making it brittle. As soon as theaters are 
fitted with floodlights so that the projectionist can put in the color, 
it will be a great advantage. 

Mr. Townsend: All I desire to say is that anything I have de- 
veloped has been done by cooperation. I would not have been able 
to do alone a quarter of what I have at the Eastman theater without 
the cooperation I received from other sources. 



Their Nature, Cause, and Methods of Prevention 

By J. I. Crabtree* and C. E. Ives*"^ 

Communication No. 236 from the Research Laboratory of the Eastman Kodak Co. 

IN MOTION picture photography the word "static" has a some- 
what flexible meaning since it is used as a contraction for both 
"static electricity" or a "static discharge," and "static markings" 
produced on a developed emulsion by an electrical discharge at the 
surface or within the emulsion previous to development. 

Although much information has been published on the nature of 
the markings produced b}^ a spark discharge at the surface of a photo- 
graphic plate/ very few data are available regarding the static mark- 
ings produced on motion picture film during handling. 

In the early days of the motion picture industry static trouble 
was feared both by camera men and laboratory workers, but as a 
result of improvements in manufacture, negative film of today 
has a relatively slight tendency to give static while our knowledge 
of methods of preventing static on positive film in the laboratory is 
such that static markings result only from incorrect handling. In 
spite of this, static markings are occasionally seen on the screen in the 
present day theatre, especially on new reels, which indicates a need 
for a better knowledge of the subject on the part of some workers. 

It is the purpose of this article to record the experience gained in 
the Research Laboratory of the Eastman Kodak Company relative 
to the nature, cause, and methods of preventing static markings dur- 
ing the handling of motion picture film. 

The Static Discharge 

If a nonconductor of electricity such as glass, sealing wax, hard 
rubber, or a drj^ nitrocellulose film is rubbed with an insulated dry 
substance, which may even be a conductor, the surface of the non- 
conducting material becomes charged with static electricity. In this 
sense, the term "static" indicates that the electricity "remains on" 
the substance. 

Precisely how the electricity is produced is not known but in 
the light of modern knowledge it may be assumed that the friction 
results in the removal of an electron from the atoms of one of the 
materials rubbed leaving it positively charged. It is generally stated 


J. I. Crabtree, Research Chemist, Eastman Kodak Company. 
' C. E. Ives, Foreman, Motion Picture Film Developing Department, 
Eastman Kodak Company. 

^ "Figm-es Produced on Photographic Plates by Electrical Discharges" 
by U. Yoshida, Memoirs of College of Science of Kyoto Univ., 1916, Vol. 2, p. 105. 


68 Transactions of S.M.P.E., August 1925 

that the sign of the charge generated by friction depends on the 
nature of the material rubbed and of the rubbing substance, although 
it is possible to charge a glass rod either positively or negatively by 
rubbing it very slowly or quickly with the same material. A substance 
may also become charged by virtue of being in close proximity to a 
second charged body when it is said to be charged by induction, 
while mere separation of two substances or variation of the distance 
between them may change their electrical potential. 

A static electrical charge is of high potential, though the quantity 
may be small, and is fairly evenly distributed over the surface of a 
flat conductor but more or less unevenly in the case of a nonconductor 
depending on the uniformity of the generation. In other words, on a 
nonconductor such as film base the charge remains where it was gen- 
erated unless it is subsequently removed in one of the following ways : 

(a) By making the air a conductor by ionization (see later). 

(b) By passing a strip of tinsel or some other conducting brush 
which is "grounded," across the surface. 

Since the earth is a good conductor of electricity and is con- 
sidered electrically neutral, if the surface of a charged body is placed 
in electrical contact with it a flow of electricity takes place either from 
the earth to the charged body, or vice versa, until it is at the same 
potential as the earth when it is said to be discharged. Such a body 
in electrical connection with the earth is said to be "grounded." 

(c) By placing a series of grounded metallic points in proximity 
with the charged surface. 

(d) If the charge reaches a certain critical value and a substance 
at a lower potential is placed near it, an electric spark jumps across 
the air gap and the nonconductor becomes more or less discharged 
over a limited area. Discharges in the manner of "a," "b," and "c" 
are termed "silent" while "d" is known as a "disruptive" discharge, 
and is of the nature of lightning which emits heat and light and is 
capable of performing mechanical work. 

Motion picture film consists of a nitrocellulose (or acetyl cellu- 
lose) base coated with a gelatine emulsion and unless specially treated, 
in the dry state both surfaces under suitable conditions will accumu- 
late an electrical charge. 

Under certain conditions motion picture film is seen to glow 
shghtly in the dark when rubbed with the hand or when subjected 
to other friction, but frequently on development no static markings 
are visible. A distinct spark, however, which is both visible and 
audible invariably affects the emulsion and produces a latent image 
of definite pattern. 

It is an open question whether static markings are a result of 
the photographic effect of light rays from the discharge or whether 
they are a result of the direct effect of the spark on the silver halide 
grains in the emulsion in which case the markings would be closely 
related to abrasion marks, or those produced by mechanical stresses. 
Experience has shown that the speed of the emulsion has not as great 

Crabtree and Ives — Static Markings on Film 69 

an effect on the intensity of the static markings produced by a given 
discharge as might be expected. 

Factors Affecting the Quantity of Static Electricity Produced 
on Motion Picture Film 

In motion picture work, electrical excitation of motion picture 
film is largely produced by rubbing. The quantity of electricity pro- 
duced depends upon the following factors : 
1. The Electrical Conductivity of the Substances Rubbed 

A . The Conductivity of the Film Base 

If a good conductor of electricity such as a metal is insulated and 
subjected to friction, an electrical charge is generated which dis- 
tributes itself more or less evenly over the surface, depending on its 
shape, and if the metal is grounded by connecting to the earth, the 
whole of the charge flows away. In view of this tendency of the 
electricity to distribute itself over the conductor, it is difficult to 
generate a charge of sufficiently high potential to produce a disrup- 
tive spark on discharging. In the case of a nonconductor the charge 
remains where it was generated and if grounded at any one spot it is 
discharged only locally. 

Therefore, if the conductivity of a substance is increased it has 
less tendency to develop a high potential locally, that is, there is a 
close parallelism between the electrical conductivity of a substance 
and the propensity for it to give static discharges. This relation is 
seen in the comparative tendency of a dried film of gelatine emulsion, 
motion picture negative film base, and ordinar}^ nitrocellulose base, 
to generate static electricity. The surface electrical conductivity 
of the materials is roughly in the order given and the tendency to 
produce static in the inverse order. 

Although a strip of comparatively dry gelatine emulsion will 
generate static, the quantity produced is so slight as compared with 
that produced under the same conditions on the film base as to be of 
negligible importance in practice, so that it is usually only necessary 
to consider the film base. 

By special treatment of the film base its conductivity may be 
increased to such an extent that its tendency to generate static is 
very much less than the untreated base. 

Since gelatine and a gelatine emulsion are much better con- 
ductors than film base it would be expected that double coated motion 
picture positive film such as is used in subtractive color photography, 
and gelatine backed film such as non-curling roll film would have a 
much less tendency to generate static than untreated nitrocellulose 
film base, and this has been found to be the case. The film conduc- 
tivity can also be increased and its tendency to generate static thereby 
decreased by increasing the moisture content as described later. 

70 Transactions of S.M.P.E., August 1925 

B. The Conductivity of the Rubbing Substance 

If the rubbing substance is a good conductor and is grounded,, 
the charge is removed as quickly as it is formed. It is important, 
therefore, from an anti-static viewpoint, that any substances which 
come into contact with motion picture film should be good conductors 
such as metal, while nonconductors such as hard rubber and glass 
should be avoided. Modern camera and motion picture machinery 
manufacturers have recognized this fact and are now constructing 
sprockets, rollers and camera gates as far as possible of metal. ^ 

2. The Amount of Friction 

In a given apparatus the greater the friction between the film 
and the parts of the apparatus the greater is the quantity of static 
liable to be produced. The degree of friction is determined by the 
roughness of the rubbing surfaces, the pressure applied and the 
relative speed of travel of the two surfaces. Therefore, in the camera 
and printer gates, the pressure applied should be a minimum and 
all parts should be as smooth as possible. In certain camera gates 
where the emulsion presses against the metal tracks more or less of 
the film emulsion tends to scrape off and accumulate as a hard mass 
on the gate, preventing the free travel of the film. In such a case 
there is a great tendency for static markings to be produced. By 
slightly lubricating the tracks with oil or grease as described later such 
gate trouble is avoided and static is eliminated. High speed of move- 
ment of the film is also responsible for static trouble when making 
slow motion pictures in the camera and when printing at an exces- 
sively fast rate, though with Eastman negative film, camera static 
even under such severe conditions is rarely encountered. In the case 
of printer static either the film should be humidified further or the 
speed of the printer reduced. 

3. The Conductivity of the Air 

Dry air is one of the best known insulators of electricity. How- 
ever, certain substances such as radio-active compounds, a red-hot 
wire or a flame are capable of ionizing the air and making it a con- 
ductor. If a charged body is placed in such a conducting atmosphere 
it tends to discharge by virtue of neutralization of its charge by the 
oppositely charged gas molecules and electrons in the ionized air 
attracted to it. For a similar reason, ionized air tends to prevent the 
accumulation of a charge on a substance during excitation by friction. 
The ionizing effect of a flame or a radio-active substance can be 
demonstrated by placing a charged electroscope close to them when it 
will be discharged immediately. Some camera workers have utilized 
the ionizing effect of a flame by fitting a small alcohol lamp below the 
camera and conducting the products of combustion into the camera 
chamber. In addition to the ionizing effect of the flame the products 

2 "Static Trouble mth the Kinematograph and Means for its Elimination," 
by A. S. Newman, Phot. Jour., June 1923, p. 262. 

Crahtree and Ives — Static Markings on Film 71 

of combustion of the alcohol contain water vapor which humidifies 
the film and renders it a better conductor of electricity. 

In the printing trade it is also customary to remove the electrical 
charge from the sheets of paper travelling through the press by pass- 
ing them immediately over the surface of a gas flame. 

Radio-active compounds are of questionable value in preventing 
motion picture static because of the expense involved in producing 
sufficient ionization, while the emanation fogs a photographic emul- 

Another method of ionizing air is by means of X-Rays. The air 
in the vicinity of an X-Ray tube is strongly ionized and a charged 
electroscope placed in the vicinity is immediately discharged. In 
order to test the anti-static effect of such ionized air an electric fan 
was arranged so as to blow the air in the vicinity of an X-Ray tube 
to a spot several feet away in a direction at right angles to the path 
of the X-Rays, and attempts were made to excite the base side of a 
strip of motion picture positive film placed in the air current but 
without success. On cutting off the current from the tube the film 
was easily excited. This experiment would suggest the possibility 
of inserting an X-Ray tube in the airducts of a motion picture labora- 
tory, though it is questionable whether the scheme would be practical 
on account of the large tube currents necessary to produce sufficient 
ionization, and the danger of fogging sensitive photographic materials 
by the X-Rays unless carefully screened. 

Humidification of the air is a sufficient and practical means of 
increasing the film conductivity and has proved effective and satis- 
factory in practice. 

The Effect of Humidification on the Propensity of Motion Picture 
Film to Give Static Markings 

Dry air is capable of absorbing or taking up a certain critical 
quantity of water in the form of water vapor at any particular tem- 
perature and atmosphere pressure, when it is said to be saturated. 
The higher the temperature the greater is the quantity of water 
vapor which the air is capable of holding, that is, the concentration 
of water vapor in warm saturated air is greater than in cold air. If 
warm saturated air is cooled, moisture condenses out leaving the air 
saturated at the lower temperature. 

The percentage of moisture in air at any particular temperature 
as compared with the quantity which it would hold if it were saturated 
is termed its relative humidity. Raising the temperature of air, 
therefore, lowers the relative humidity providing no water is present 
for the air to absorb, and vice versa. 

Relative humidity measurements are usually made by a hygrom- 
eter, a suitable form of which consists of a wet and dry bulb ther- 
mometer. The bulb of the wet thermometer is surrounded with an 
absorbent material such as a silk wick which dips into a vessel con- 
taining water. The evaporation of this water tends to cool the bulb 

72 Transactions of S.M.P.E., August 1925 

and since the rate of evaporation depends on the dryness or relative 
humidity of the air, the difference in reading between the wet and dry 
thermometers is a measure of the relative humidity of the air. It 
is important when using a hygrometer to place it in such a position 
that a representative sample of the air circulates over it. By reference 
to tables supplied with the instrument the relative humidity is ob- 
tained. Some hygrometers rely on the expansion and contraction of 
a strand of horsehair in dry and moist air but these are not always 

If motion picture film is placed in an atmosphere at any relative 
humidity there is an exchange of moisture either from the film to the 
air or vice versa until equilibrium is reached. That is, dry film in a 
moist atmosphere absorbs water while moist film in a dry atmosphere 
loses water. 

The transfer of moisture either from the air to the film or vice 
versa requires time and takes place comparatively slowly. 

Since the tendency of film to give static markings depends on its 
conductivity which in turn depends on the absolute quantity of 
water which it contains, the effect of moist air in affecting the pro- 
pensity of film to give static depends on 

a. The relative humidity and temperature of the air. 

b. The time of exposure of the film to the air. 

(a) In order to determine the effect of humidification in atmos- 
pheres of increasing relative humidity on the propensity of gelatine 
and film base to generate static electricity, strips of motion picture 
positive film and sheets of gelatine were exposed to atmospheres of 
different humidities by placing in humidors containing sulphuric 
acid of varying concentrations (representing atmospheres of known 
relative humidity) and stored for 12 hours at temperatures of 50° F., 
and 110° F., respectively. The strips were then rubbed vigorously 
with a piece of velvet (the positive film was rubbed on the base side) 
and tested for electrification by means of an electroscope. The results 
obtained were as follows: 

Relative Humidity 


From these tests it is seen that gelatine ceases to generate an 
appreciable amount of static- electricity when exposed to an atmos- 
phere of about 80% relative humidity for twelve hours, at 50° F. 


y Material 50° F. 

110" F. 

Gelatine slight 


M. P. Positive Film strong 


Gelatine slight 


M. P. Positive Film sHght 


Gelatine nil. 


M. P. Positive Film slight 

very slight 

Gelatine nil. 


M. P. Positive Film very slight nil. 

Gelatine nil. 


M. P. Positive Film nil. 


Crahtree and Ives — Static Markings on Film 73 

Although tests were not made with sheets of emulsion stripped 
from the base, comparative tests made by rubbing gelatine sheets 
and the emulsion side of motion picture film exposed to the same 
atmosphere, showed that positive and negative motion picture emul- 
sions have less tendency to generate static electricity than plain gela- 

The above tests also show that with motion picture negative 
film the air must have a relative humidity of about 90% at 50° F. and 
about 85% at 110° F. if it is to entirely prevent the generation of 
static electricity when the film is exposed to it for a few hours. 

Since with air at any constant relative humidity the quantity 
of water which it contains increases with rise of temperature, film in 
equilibrium with such air contains a greater quantity of water at 
higher temperatures. Since the propensity of film to give static mark- 
ings runs parallel with the absolute quantity of moisture which it 
contains, it would be expected that at a given relative humidity the 
propensity of film to give static would decrease with rise of tempera- 
ture, as was shown by the above experiments. 

(b) A dry emulsion or a dry film base absorbs moisture com- 
paratively slowly. Bone dry motion picture film must be humidified 
for more than 24 hours in an atmosphere at 80% to 90% relative 
humidity before it absorbs all the moisture it will hold under these 
conditions. Hence, the condition of the air has very little effect unless 
the film is exposed to it for a sufficient length of time. Thus, dry 
motion picture positive film may give static markings even if the 
air of the printing room is saturated, if the film is not given an oppor- 
tunity to absorb moisture. On the other hand, film containing an 
excess of moisture will not give static markings when immediately 
placed in dry air. 

The fact that motion picture film is usually tightly rolled also 
hinders the rapid attainment of equilibrium with the atmosphere, 
but this is advantageous, in case film has to be stored in a dry atmos- 
phere. If conditions are such that static markings are produced on 
positive film in the laboratory, in order to further humidity the film 
in the roll it must be stored for several weeks in a moist atmosphere, 
but not one which is too moist, otherwise the edges of the film will 
stick together and on unwinding more static will be produced than if 
the film was handled in its original condition. 

Nature and Classification of Static Markings 

Static markings produced directly on an emulsion are invar- 
iably black, and in the case of a negative, they print as white mark- 
ings on the positive print. The markings frequently occur at regular 
intervals owing to the intermittent movement of the film in the 
camera or printer gate (see Fig. 10), although more often the occur- 
rence is at irregular intervals. 

If the friction on the film is local the discharge usually takes 
place in the same vicinity, but if the friction is evenly distributed over 

74 Transactions of S.M.P.E., August 1925 

the film surface the discharges occur at irregular intervals and in no 
particular location. Very frequently the markings are confined to the 
region of the perforations and occasionally extend inwards from the 
edges of the film. 

With normal development the density of the markings may vary 
from a just visible deposit to a relatively high density according 
to the severity of the discharge. 

In shape, static markings consist of either dots or irregular lines 
or a combination of the two. 

The appended illustrations are of static markings accumulated 
over a period of several years and were produced either in the camera 
or the printer. The exact conditions under which they were produced 
were not recorded but it was only possible to secure such severe mark- 
ings by drjdng out either positive or negative film very thoroughly 
in a desiccator. 

Such well-defined and frequentty occurring markings are rarely 
found in practice, but it was necessary to make the conditions as 
favorable as possible for their production in order to secure markings 
suitable for illustration purposes. 

The figures merely illustrate the type of markings which may 
occur under more normal conditions. Although the variety of the 
markings is possibly not complete it is doubtful if any essentially 
different types of markings are normally produced in the camera or 

Static markings may be classified as follows : 

1. Small black spots with diffused edges. These markings are very 
similar to a certain type of moisture spots, ^ or spots caused by chem- 
ical dust. Fig. 1 illustrates a large cluster of spots disseminated 
throughout a fan-shaped marking produced in the camera. This 
type of marking occurs very rarely. 

2. Black spots with branches. In Fig. 2 the black spots have one 
or two branches while in Fig. 3 several branches radiate from the 
central dark spot, simulating a spider with outstretched legs. 

3. Tree-like markings as shown in Figs. 4 and 5. These are a 
modification of those shown in Fig. 2 since the tree trunks and branches 
emanate from a black spot. The branches may also be regarded as 
sprouting from an imaginary horizontal bar at the base. The mark- 
ings illustrated in Figs. 2, 4 and 5 were produced in the camera with 
bone dry negative film and the intermittency of occurrence is clearly 
seen in Figs. 4 and 5. 

4' Fan-shaped markings as illustrated in Figs. 6, 7 and 8. The 
radii of the fan may be considered as branching out from a point 
which may possibly be the initial point of discharge. The markings 
in Fig. 7 consist of an assemblage of fan markings and were produced 

3 "A Study of the Markings on Motion Picture Film Produced by Drops of 
Water, Condensed Water Vapor, and Abnormal Drying Conditions," by J. I. 
Crabtrpe and G. E. Matthews, Trans. Soc. M. P. Eng., Vol. 17, p. 29. 

Crahtree and Ives — Static Markings on Film 75 

in a step printer. The intermittent occurrence of these is shown in 
Fig. 11. 

In Fig. 6 the lower half of the fan-shaped marking is of much less 
density than the upper half and not so sharply defined, and is probably 
a result of either a reflection of the upper discharge, or a secondary 
weak discharge. 

S. Miscellaneous markings. Those shown in Fig. 9 were produced 
on bone dry negative film in a camera and consist of a conglomeration 
of dots, branches, and fans. 

Static Markings Encomitered in Practice and Methods of Their 


AVhen motion picture film leaves the factory it may be reason- 
ably assumed that it is free from latent .static since it is handled 
during manufacture with extreme care and under the most ideal 
conditions of humidit}^ Moreover, careful tests are made on the 
finished perforated film before shipment in order to insure that the 
film is free from latent static markings which might otherwise appear 
on the developed film. 

During handling, static may be produced either in the camera 
or in the laboratory when winding the film onto racks, when processing 
on the developing machiDe, or during printing as follows: 

Camera Static 

Negative motion picture film when packed for shipment con- 
tains such a quantity of moisture that it is in equilibrium with an 
atmosphere of 70% to 75% relative humidity, and in this condition, 
and especially in the case of negative film, unless it is subjected to 
severe friction, no static trouble need be feared in practice. 

In order to determine at what point or points in a camera static 
is usually generated, a roll of positive motion picture film was thor- 
oughly desiccated over sulphuric acid and then passed rapidly through 
a camera in the dark. Static discharges were observed at the following 
points: (a) where the film parted from the spool at a tangent, (b) at 
the retort traps, (c) in the region of all sprockets even though grounded, 
(d) at the gate, (e) at the take-up roll. 

So-called grounded collectors consisting of tinsel and graphite 
coated pads were placed against or near the film at two or three 
places but these had very little effect in preventing the static dis- 
charges. On development of the film the quantity of static markings 
ran parallel with the quantity of discharges observed in the dark. 

This experiment demonstrated that static may be produced in 
the camera at any point where there is friction and especially in the 
camera gate where the discharges were most severe. It was also 
concluded that brush collectors are of questionable value, while a 
grounded metal crank is of little use unless the handle is in electrical 
connection with other parts of the camera such as the gate and 
sprockets, which must be good conductors. 

76 Transactions of S.M.P.E., August 1925 

Prevention of Camera Static 

The only certain method of insuring the absence of static mark- 
ings is to prevent the generation and accumulation of the static 
electricity in the first place as follows: 

1. By removing all sources of friction. Negative film which 
shows camera static markings generally also shows bad abrasion 
marks. Of the various parts of the camera the gate is responsible for 
most of the abrasion. 

When making titles directly onto positive film in the camera 
the emulsion tends to scrape off onto the metal tracks where it builds 
up excressences of hardened emulsion which retard the passage of 
the film and incidentally cause static as a result of the increased 
friction. By glueing a small strip of oiled chamois on each side of the 
film track at its upper edge the passage of the film is facilitated and 
abrasion of the emulsion and the attendant static is prevented. 

Film loops which are too long cause the film to rub either against 
itself or the side of the camera with the possible generation of static. 

2. By making all camera parts conductors of electricity. As ex- 
plained above, when film is rubbed with a conductor such as a metal, 
a minimum of static is produced especially if the metal is in electrical 
connection with the rest of the camera or is * 'grounded." Glass, hard 
rubber, varnished or lacquered metallic surfaces, silk and velvet 
should, therefore, be avoided whenever possible in camera construc- 
tion, while the gate and sprockets and as far as possible every part 
of the camera should be of metal. 

3. By rehumidifying the film. Negative film which is stored for 
considerable periods in a dry atmosphere loses moisture, but may be 
rehumidified by rewinding loosely and storing for about 12 hours in a 
humidor, consisting of an enclosed box containing either a sponge 
or other absorbent material saturated with water. A simple humidor 
may be constructed by soldering together two motion picture film 
cans bottom to bottom, perforating the now common partition and 
placing saturated blotters in one of the compartments. The loosely 
wound film should then be placed in the empty compartment and 
allowed to remain for about 12 hours at 70 to 75° F. The film should 
not be allowed to remain for too long a period in the humidor, especially 
at high temperatures (80 to 90° F.), otherwise moisture spots are 
liable to be produced on the emulsion.^ 

The practice of placing a moistened sponge in the camera is of 
no value if the film is run through quickly, but if the sponge is allowed 
to remain in the loaded camera for one or two hours the film has more 
opportunity to absorb water and may be less liable to develop static 

4- By conducting the products of combustion of an alcohol lamp into 
the camera chamber. Since the products of combustion of alcohol 
contain water vapor, the lamp has a two-fold effect of humidifying 
and ionizing the air which as explained above tends to prevent static. 

Crahtree and Ives — Static Markings on Film 77 

Laboratory Static 

In the motion picture laboratory static discharges may occur 
during the following operations (a) Winding the film on the developing 
racks, (b) Development on the processing machine (c) Cutting of the 
negative and (d) Printing. 

1. Rack Static. 

Film is usually wound on the rack by holding the roll of film in 
one hand and winding with the other. The slack film is then tightened 
by pulling on each loop which results in severe friction between the 
slat and the film base, which may result in static markings. 

Static discharges may also occur at the point where the film 
leaves the roll at a tangent as a result of induction and friction, 
especially if the film has been humidified excessively causing the con- 
volutions to adhere slightly, while if the roll is gripped at all tightly, 
friction between the hand and the film or between the convolutions 
of the film may be sufficient to cause static. The latter difficulty may 
be overcome by the use of a roll holder illustrated in Fig. 12 during 
winding. The arm AB is lifted up, the roll placed on core C and the 
arm AB again lowered. The holder is then grasped by handle H, and 
by exerting a slight pressure with the thumb at A the film may be 
fed with a uniform tension and speed. 

Static markings produced during winding and tightening may -be 
minimized by humidification of the film before it enters the dark 
room, and in severe cases by also humidifying the air in the dark 
room. A suitable relative humidity is from 70% to 80% at 70° to 
75° F. 

2. Developing Machine Static. 

On a processing machine static markings can only be produced 
up to the point where the film enters the developer, and may be 
caused by too much tension on the take-off roll, malalignment of 
the sprockets, or by running the machine at too high a speed. Humid- 
ification of the film previous to or during printing, and correction of 
mechanical defects will prevent such trouble. 

3. Electrification of Negative Film in the Cutting Room. 

Since electrified film has a powerful attraction for dust particles, 
it is important to maintain a fairly high humidity in the cutting room 
in order to minimize the propensity of the electrified film to attract 
dust. Such humidification also tends to prevent printer static. 

4. Printer Static. 

The largest proportion of static markings encountered in the 
laboratory are produced during printing, and especially with step 
printers. Static is rarely encountered with all-metal continuous 

In a step printers the film is subjected to excessive friction during 
the pull-down movement, especially with shrunken negatives. Static 
markings may, however, be prevented :- 

78 Transactions of S.M.P.E., August 1925 

1. By avoiding friction. All sprockets should be of correct dimen- 
sions and in alignment with the take-up roll. If the sprocket teeth 
are staggered, or if the take-up roll is in malalignment, excessive 
tension is exerted on one edge of the film. Too much tension should 
also be avoided at the take-up roll, while the loops should be adjusted 
to prevent any possibility of the film rubbing against itself or any 
part of the machine. 

The printer should also be correctly "timed," that is, the pressure 
plate should be released before the pull-down movement commences 
and should not return in place before the film comes to rest. Although 
glass is not an ideal material for pressure plate construction in view 
of its nonconductivity, metal plates are unsatisfactory where a trans- 
parent plate is otherwise desired, while glass produces a minimum of 
scratches on the film. The pressure plate should be renewed whenever 
the surface becomes roughened. 

2. By humidifying the film. When motion picture positive film 
leaves the factory it is in equilibrium with an atmosphere of 70 to 
75% relative humidity, but if the laboratory conditions are favor- 
able for the production of static markings the quantity of moisture 
which the raw film contains is not sufficient to positively insure the 
absence of static during processing. It would be dangerous, however, 
to humidify the film further during manufacture, owing to the danger 
of the formation of moisture spots when the film is stored.^ Since a 
certain lapse of time is necessary for moisture to affect the emulsion, 
it is possible to humidify film immediately previous to or during 
processing to an extent which would be dangerous if the film was to be 
subsequently stored. 

3. By humidifying the air in the printing room. If the printers 
were always in perfect adjustment and not run at too high a speed, 
a higher relative humidity than 75% at 70° to 75° F. would not be 
necessary in the printing room. In order to take care of the excessive 
friction to which the film is liable to be subjected if the printers get 
out of adjustment it is advisable to maintain the relative humidity 
at from 80% to 90% at 70° to 75° F. At such a high relative humidity 
the air feels uncomfortably cool to the worker at temperatures below 
68° F. and oppressively warm above 75° F. 

The exact relative humidity to be maintained depends on the 
particular machines used, the condition of the film, the temperature 
of the air, and time during which the film is exposed to the air before 
it is subjected to friction. The higher the temperature the lower is 
the relative humidity necessary to overcome a given tendency for 

Usually the film is exposed to the air for only a few seconds before 
reaching the printer gate. This period may be prolonged by looping 
the film over several idler rollers before it reaches the gate. Such a 
procedure, however, is usually unnecessary if the negative is humidi- 
fied us described below. 

Crahtree and Ives — Static Markings on Film 79 

Methods of humidifying the air supply have been fully described 
in a previous communication.* Since the air in the printing room is at 
a higher relative humidity than that in any other room, it is necessary 
to boost the humidity of the air supply locally, and this can be readily 
accomplished either by means of water spray jets or steam jets. A 
series of water spray jets operated by compressed air and inserted 
in the air line serve to immediately change the relative humidity and 
have the advantage of cooling the air in hot weather. In winter both 
steam and water sprays are often necessary. 

4. By humidifying the negative previous to printing. One con- 
tributing factor in the production of printer static is the friction 
between the gelatine surface of the negative and the emulsion side of 
the positive film in the gate, and especially during the pull-down 
period with old, dried out, shrunken negative. This can be largely 
overcome by humidifying the negative previous to printing by re- 
winding slowly two or three times in an atmosphere of 80% relative 
humidity, or by treating the emulsion side of the film with a solution 
of grain alcohol containing 10% to 20% water. Treatment of the 
film with this solution would insure that it would not attract dust in 
the cutting room, while it would assist in the prevention of static 
markings on positive film in the printer. 

Dangers of Over-Humidifying Motion Picture Film 

Too much humidification of film is worse than none at all for the 
following reasons : 

a. Moisture spots are liable to be produced if drops of water 
condense on the emulsion.^ 

b. On winding moist film, the convolutions may adhere locally 
causing ferrotyping of the emulsion surface by virtue of being in 
contact with the polished base. On rewinding, the local adhesion of 
the film may cause more static markings than if the film had not been 
humidified in the first place. 

c. Moistened film is more susceptible to thumb prints and abra- 
sion marks than dry film. 

d. Film which is too moist is apt to stick in the printer and may 
cause a stoppage, tearing of the perforations, or unsteadiness of the 
picture on the screen. Moist film is also apt to buckle causing lack 
of contact in the printer with resulting loss of definition. 

* "The Development of M. P. Film by the Reel and Tank Systems," by 
J. I. Crabtree, Trans. Soc. M. P. Eng., Vol. 16, p. 163. 


Transactions of S.M.P.E., August 1925 

Fig. 1 — Fan-shaped camera static 

Fig. 3 — Spider-like camera static 

/( 1 

Fig. 2 — Black spots and boomerang 
shaped static markingstproduced in the 

Fig. 4 — Tree-trunk camera static 

Fig. 5— Camera static markings re- 
sembling tree trunks with base Une. 

Fig. 6 — Fan-shaped static marking 
produced in a step printer. 

Crabtree and Ives — Static Markings on Film 


Fig. 7 — Printer static markings. 

Fig. 8 — Fan-shaped static markings 
sprouting from edge of film. 

Fig. 9 — A conglomeration of fan-shaped 
and tree-Hke static markings produced 
in the camera. 


Transactions of S.M.P.E., August 1925 









o. . 

o ; 




O 1 

I ^ 

CJ o: 

'"1 * 











c i 

i Cj 


1 Zj 

Fig. 10 — Illustration showing the inter- Fig. 11 — Illustration showing the inter- 
mittency of occurrence of camera mittency of occurrence of step printer 

static markings. static markings. 

Si<le Elcvatiorx- 

1^11 Holder/hr R^ck Winding 

Fig. 12 — Roll holder for winding motion picture film onto racks. 


Mr. Fritts: If we have two spheres near each other at a high 
potential, the only way a discharge would take place would be by 
eruption. If the balls were replaced by sharp points, then the dis- 
charge does not reach the point of eruption but leaks off as a brush 
discharge. Would it not be possible to place such points near the film 
in the camera so that the charge would be carried off by the ionized 
air surrounding such points? 

Mr. Renwick: This paper will be very valuable I am sure to 
our members for it is of a very practical character. 

The friction side of the matter has been stressed however. I 
do not believe from my observations that the amount of pressure 
exerted has much to do with the amount of electricity generated. 
Then, again, it is stated that it is very difficult, even impossible, to 
produce static by running a motion picture film over a metallic con- 
ductor. That is not correct, and as a matter of fact I believe Mr. 
Crabtree corrects himself a little later when he says that tinfoil was 
not a preventive of static. 

I was a little surprised that he did not mention the subject of 
contact potentials, nor did he mention the possibility of avoiding 
static by altering the character of the materials coming into contact. 

Dr. Mees: Mr. Crabtree wanted to write a paper intelligible 
and valuable to operators and motion picture printers. We discussed 
whether the origin of static electricity should be dealt with. First of 
all, it is a controversial question; we do not feel it is cleared up from 
the chemical point of view and we thought that laboratory operators 
would not be interested in it. They are getting marks on the film and 
want to know how not to get them, and the paper was designed from 
this point of view. 

With regard to friction, it was not intended to suggest that 
friction is the cause of static, but intimacy of contact is the cause of 
friction and also of static. 

Mr. Crabtree: About Mr. Fritts' suggestion, all I can say is 
that we will try it out. 

I agree with Mr. Renwick that we can get static by rubbing with 
a conductor but experiments have shown that the intensity is less 
with a grounded metallic conductor than with an insulated one under 
the same conditions. There is no doubt that all-metal cameras have 
much less tendency to give static than the old type wooden cameras 
containing hard rubber rollers, velvet pads, and so forth. We have 
not made specific experiments to show the relative quantity of elec- 
tricity produced with metal and velvet under the same conditions. 
Of course, our knowledge of the theory of static is very slight and in 
making experiments it is very difficult to control accurately all the 


84 Transactions of S.M.P.E., August 1925 

factors involved. The printed paper is merely a record of the results 
of practice. Humidification of the film, the elimination of friction 
and the rapid motion of anything near or against the film tends to 
eliminate static. By observance of these points we can practically 
eliminate it. From the standpoint of the laboratory worker and the 
camera man that is all he needs to know. 

Mr. Renwick: I appreciate what Dr. Mees and Mr. Crabtree 
have said about the value of looking at this thing from the point of 
view of the practical man but sometimes a paper from that point of 
view may be misleading. May I suggest that there is no reason why 
you cannot get very bad static between metals and motion picture 
film if only you separate them fast enough. If, however, separation 
takes place very slowly, you get leakage, and that is why the con- 
clusion has been reached that metal conductors in contact with the 
film give lower potential charges. 


By M. Briefer* 

Communication from the Photographic Department Atlantic Gelatine 
Company, Woburn, Mass. 

WE FIND in "Investigations on the Theory of the Photographic 
Process,"^ that as early as 1840 the sector wheel, a disk with 
successively increasing angular apertures, was proposed by 
Claudet. Hurter and Driffield adopted a sector wheel having nine 
apertures, ranging from 180 degrees for the largest, to 0.703 degrees 
for the smallest, each succeeding angular aperture from the center 
being hah that of the preceding one (Fig. A) . The disk is caused to re- 
volve before a light source usually at one meter distance. A sensitive 
photographic emulsion, sufficiently exposed behind such a disk, is 
impressed with nine different light exposures, the ratio of any ad- 
jacent pair being as 1 : 2. The radius of this disk, measuring from 
the center to the circle including the outermost aperture, is about 
12 cm. The usual procedure is to expose to a constant light intensity 
for different times as occasion demands. 

One objection to the sector wheel as a time exposure scale, arises 
from the difficulty in cutting the smaller angles accurately. In order 
to reduce the error in these small angles, the Bureau of Standards 
has adopted a disk of about twice the usual diameter, and also in- 
creased the radial length of the apertures from 10 to about 13 milli- 
meters. A disk of about these dimensions is in use also, at the ]\Iassa- 
chusetts Institute of Technology. Another objection is based upon 
the difference in the photographic effect, between intermittent and 
continuous exposure, and is known as the failure of the Bunsen- 
Roscoe "reciprocity law." The failure of intermittent exposures to 
intergrate, presumably varies with the ratio of exposure time to the 
time of intermittency; that is, the failure is gi-eater as the inter- 
mittent period is increased. Some attempts have been made to avoid 
intermittenc}" errors, with de\ices to affect exposures with one com- 
plete revolution of the disk; but the mechanical difficulties have been 
considerable, and besides the "speed"' readings so obtained, would be 
applicable only to the time of exposure used. The rotating disk per- 
mits variation of the time of exposure to a constant light intensity, 
the densities so obtained, being the product of intensity and time. 
This has proven the most convenient method, and the easiest to 

The sector wheel to be described (Fig. B), is not a radical 
departure from the conventional type, but a simple modification of it ; 

* Atlantic Gelatine Co. 
^Sheppard and Mees. 



Transactions of S.M.P.E., August 1925 

yet, two principal objects are attained in the design; first, simplicity 
in laying out the angles, and secondly, greatly reducing the possibility 
of error in cutting the apertures. Incidentally, since the inter- 
mittent period of one revolution of the disk, is reduced from 50 
to 29 per cent, the intermittency error should be correspondingly 


Conventional Sector Wheel 

less. Also, the effective exposure for each revolution is greater by 
nearly 43 per cent, thus affecting considerable economy of time 
in doing work. 

The diagram shows the plan of the proposed sector wheel, and 
is self-explanatory. The angles are laid out beginning with one whole 

Briefer — An Improved Sector Wheel 


degree for the smallest, and ending with 256 degrees for the largest, 
each angle from the center being twice the preceding. The design 
is such that there are no fractions of degrees used anywhere. With a 
little care and some patience, the angles may be laid out to a high 
degree of accuracy with the aid of a good protractor. In the di- 
mensions given, a radius of 18 cm. is taken for the smallest angle 
making the aperture approximately 4 by 10 mm. This is about the 


'Improved Sector Wheel 

dimensions of the third smallest aperture of the conventional type 
sector wheel. Obviously, accurate cutting is greatly facilitated. 
Those without facilities for precision measurements, may cut a good 
sector wheel of the proposed pattern with ordinary fine tools. 

It will be noted that the largest angle (256°) is laid out in three 
sections; two of 85 degrees, and one of 86 degrees. The second largest 
angle (128°) is in two sections, 86 and 42 degrees while the three 
solid sections are 35, 35, and 34 degrees. This slightly unbalanced 

88 Transactions of S.M.P.E., August 1925 

division of the disk has no effect on the photographic result and is 
warranted from the fact already noted — doing away with fractions 
of degrees. 

The large disk diameter, (38 cm.) permits a greater radial 
length for the apertures, but one centimeter each, is quite enough 
for all practical purposes. Exceeding a total length of nine centi- 
meters at one meter distance from light may make the marginal 
errors, from the difference in sines, appreciable. 

The disk should be mounted on a large hub having three radial 
spokes to serve as a rigid support. The hub shaft may be run on 
ball bearings, and the whole carefully balanced for smooth running. 
Following is a tabulation of relative values. 

Improved Sector Wheel 


Comparative Values 

(A). (B) 

Conventional Proposed 

Type Type 
Angles in Degrees 

180. 256. 

90. 128. 

45. 64. 

22.5 32. 

11.25 16. 

5.625 8. 

2.813 4. 

1.406 2. 

0.703 1. 

(A) . (B) 

Ratio of Apertures to 360 

.5 .711 

.25 .355 

.125 .1775 

.0625 .08875 

.03125 .044375 

.015625 .022188 

.007813 .011094 

.003907 .005547 

.001953 .002773 

Effective Exposure 
50% 71.1% 

Ratio of Angular Apertures 
1 : 1.428 


Mr. Renwick : I think that the sector wheel Mr. Briefer proposes 
has some constructional advantages over the ordinary type but the 
greatest advance made in sector wheel sensitometers is described 
by Dr. A. C. Hardy in the February issue of the Journal of the 
Optical Society of America. In this apparatus, two wheels are miade 
to work together and a series of single exposures covering an extra- 
ordinarily long range is possible by this means. 

Mr. Briefer: Mr. Hardy's wheel, which is at the Boston Tech, 
I have seen in operation. It is very ingenious but difficult to build. 
My object is to promote simplicity and to make it possible for 
amateurs to construct a sector wheel without difficulty. 



This paper describes the manufacture of Incandescent Motion Picture 
Lamps and points out some of the manufacturing variables affecting lamp 

By Robert S. Burnap* 

INCANDESCENT lamps can be easily described. They consist 
of a solid filament made hot electrically glowing in a transparent 
container which contains no filament attacking material. The 
manufacture of the ordinary incandescent lamps is not so easy to 
describe because the process involves the handling of a peculiar 
metal tungsten, the obtaining of gas tight seals for lead wires, the 
working of glass, and the removal of all oxygen or moisture from the 
container. The manufacture of lamps for projection or motion picture 
service is still more exacting for we must concentrate the filament 
source, reduce bulb sizes, and increase operating temperatures. 
Design to obtain maximum projected light means a reduced factor of 
safety as far as manufacture is concerned. 

This paper will be limited rather closely to the manufacture of 
the 900 watt 30 ampere motion picture lamp. This lamp is intended 
for operation at constant current and is used chiefly for motion picture 
projection. (Fig. 1.) The filament consists of four parallel coils in series 
supported from two heavy nickel lead wires. The leadwires conduct 
the current to the filament from the brass base thru a gas tight seal. 
The filament is supported by top and bottom anchors so designed as to 
not cause filament strains during the lamp life. Incidentally, the cor- 
rect design of the super-structure for the mount involved a problem 
in structural design where the parts must withstand a 3000° C change 
of temperature every quarter of an hour and where the filament after 
many such cycles must show little distortion. The filament is sur- 
rounded by an inert gas consisting mostly of argon. The bulb is of 
hard glass to withstand the high operating temperatures and is made 
narrow to allow the filament to be placed close to the condensing 
lens, and high to provide a depositing chamber for the tungsten which 
evaporates from the filament and is carried upward by the heated 
gas. Generally the lamp is operated with a concave mirror which is so 
adjusted that the filament image is meshed with the filament to 
completely fill the sections between the parallel coils and to present a 
solid light source to the condensing lens. 

The first step in this description of the manufacture is the tung- 
sten filament. Tungsten itself is obtained as ore from China. This ore 

* Edison Lamp Works of G. E. Harrison, N. J. 


Burnap — Manufacture of Motion Picture Lamps 


Fig. 1.— 900 Watt ampere 

Lamp for Motion Pictm^e 


92 Transactions of S.M.P.E., August 1925 

is known as Wolframite and consists of iron, manganese and tungsten. 
The ore is treated to obtain pure tungsten in the form of a powder 
which is pressed into slugs under hydraulic pressure. The slug is 
heated electrically in hydrogen to sinter the powder and then worked 
by swaging and drawing to the required size. The handling of tungsten 
is peculiar in that the metal is never in a molten state and in that 
working the metal makes it more ductile. Annealing as we ordinarily 
understand the term for metals makes tungsten brittle. 

Since a nontwisting, nonsagging material is required for the fila- 
ment, the metal is treated and tested for these qualities. After having 
obtained a satisfactory wire, the wire is coiled on a lathe equipped to 
space the sections correctly. (Fig. 2.) The mandrel is removed by treat- 

Fig. 2. — A. Coiled Filament on Mandrel; B. Formed Filament 

ment in acid. The coiled lengths are fired in hydrogen to clean them 
and to remove strains and then bent to shape over a heated wire. This 
is a task requiring skill for the tungsten wire is somewhat brittle and 
difficult to handle in this large diameter. The loops must be correctly 
formed to lock with the anchors. 

The manufacture of the stem presents difficulties not at first 
apparent, for this part of the lamp not only supports the finished 
filament but also forms the seal through which the lead wires pass. 
The stem consists of a flared glass tube of which the unflared end is 
pinched about the sealing in wires, the hub cane which supports the 
bottom anchor guides, and the exhaust tube which ends with a small 
opening just below the seal pinch. (Fig. 3.)The lead wires consist of 
three parts, a nickelsection which carries the filament, a tungsten sec- 
tion which forms the seal, and a flexible copper strand for attaching to 
the base. It is not only essential to have a gas tight seal but also to 
proportion the parts and to fuse the glass so that no strains in the glass 
are obtained. The actual forming of the stem is done on a rotary 
spider^ carrying heads which align the parts and which pass thru 

Burnap — Manufacture of Motion Picture Lamps 


Seal Pinch 

Exhaust ^^ 

Top Bridge 
Lead Wire 

Exhaust Tube 

Fig. 3.— 900 Watt 30 ampere Mount 


Transactions of S.M.P.E., August 1925 

Fig. 4.— Stem Machine 

Bitmap — Manufacture of Motion Picture Lamps 95 

various fires each of which has a certain function to perform in forming 
the seal. (Fig. 4.) After the glass is heated in an oxygen and gas flame 
to the correct temperature, two jaws clamp the softened glass firmly 
to form the seal or pinch about the seahng in wires. The small exhaust 
hole is formed by a puff of air into the exhaust tube. The air pressure 
forces an opening thru the side of the softened pinch. This method of 
making stems results in the elimination of the tip which was so 
objectionable in the past. 

The next operation is the mounting of the filament in the correct 
position on the lead wires. This is done by an electrical weld made 
with high current which is automatically timed by a relay. The top 
bridge and anchors of molybdenum are attached in the same manner. 
The bottom swing w^hich slides in the vertical guide sections is also 
attached and carefully adjusted to eliminate possibility of binding. 
The mount is flashed at full current in a bottle containing hydrogen 
to relieve any filament strains, and then is cleaned in an electrolytic 
bath. After cleaning the mount is again flashed and tested for free- 
dom of moving parts. 

The skill with which the mounting is done determines to a major 
degree the quahty of the lamp. Ununiform mounting or filament dis- 
tortion produces a streaked and unsatisfactory screen. The manu- 
facturer is not only concerned with the problem of producing wire 
which is free from strains, but also with supporting and attaching 
the filament so that no additional strains are produced. To date no 
satisfactory mechanical method for mounting the more complicated 
projection lamp filament types has been developed so that results 
are dependent on skill by hand. This is a job requiring skill for fila- 
ment distortion is caused by very minor mounting strains. These 
strains particularly^ on the smaller projection lamps set a practical 
limit to concentration of filament source. 

The joining of the flare of the stem to the bulb is done on a 
machine somewhat similar to the stem machine, and requires oxygen 
and gas fires due to the hardness of the glass. (Fig. 5). 

The removal of the air and moisture and the filling with argon 
gas is performed on a large rotary machine which carries tbe lamp thru 
a heater where the lamp is heated to 500° C. The air is removed by a 
series of washes with nitrogen gas which simply dilute the air to a 
neghgible quantity. The various ports on which the lamp is placed 
are automatically connected by means of a rotary valve to the pumps, 
the nitrogen, and the argon supply lines, as the machine indexes. 
Constant checks are made on this machine for even a very small leak 
affects the lamp quality seriously. (Fig. 5). 

The lamp is sealed off by fusing the glass exhaust tube while 
still on the exhaust machine. The lamp is then transferred to the 
baser who threads the lead wires thru the base which has been pre- 
viously filled with cement. The lamp base is then heated on a rotary 
machine to set the cement. (Fig. 5). 

After basing the lead wires are electrically arc welded to the 
base terminals to insure positive connection. The lamp is then tested 


Transactions of S.M.P.E., August 1925 


Burnap — Manufacture of Motion Picture Lamps 97 

for accuracy of physical dimensions on a special machine which pro- 
jects the filament image upon a chart. (Lamps outside the chart 
diagram limits are rejected). (Fig. 6) After holding for several days 
to allow glass defects to develop, the lamps are aged at over current, 
reinspected and packed ready for shipment. 

Fig. 6.— Light Center, Axial Alignment, and Source Size Checking Machine 

So far very little has been said about the checks which are placed 
about the product to insure good quality. These checks are very 
necessary for this is an article where a very small reduction in wire 
size seriously affects the life of the lamp, where slight variations in 
materials and methods affect the accuracy of the glass parts, where 
slight strains in the filament may cause early failures due to short 
circuit, and where poor exhaust conditions cause early bulb black- 
ening. All of these conditions affect the quality of household lamps, 
but the more exacting duty of the motion picture lamp or projection 
lamps emphasizes poor performance when it is obtained. The manu- 
facture of tungsten wire which will always perform the same, the 
obtaining of perfect exhaust and the manipulation of glass are still 
far from the state of being exact sciences. This being the case a series 
of checks on the lamp manufacture is made thruout manufacture 
from tungsten metal to finished lamp. 


Transactions of S.M.P.E., August 1925 

In addition to the checks which are a routine of manufacture, all 
metal is tested for nonsag and nontwist characteristics by making 
and burning specially constructed lamps. The final product is checked 
by periodically selecting lamps which are operated under service 
conditions in the Life Test Department. Here lamps are rated for 
candlepower and read for screen illumination during life. (Fig. 7) 


-Photometer Test 

Life tests are made in standard housings under intermittent condi- 
tions of burning with accurate current control. (Fig. 8) Another source 
of lamp performance information is lamps returned from customers. 
The defects are analyzed and when necessary changes in method 
of manufacture are made to improve the product. 

Just a word on the effect of burning at other than rated voltage. 
An increase of one per cent in amperes or two per cent in volts reduces 
the life approximately twenty per cent but gives three per cent greater 
illumination. An excessive increase in voltage decreases the safety 
factor against surges in the voltage supply. 

Lamps consume watts and as a result get hot. The equipment 
manufacturer should make all provision possible for getting rid of 
this heat. Lamps for projection purposes are intentionally made 
small to help make compact equipment, but the result is to reduce the 
factor of safety against excess lamp temperature. 

Burnap — Manufacture of Motion Picture Lamps S9 

This paper has not attempted to cover probleras of design which 
have been met in the development of the incandescent motion picture 
lamp. It is desirable however to point out that the material tungsten 
with which we work can not be operated satisfactorily much above 
3300° K, and that excessive concentration of the filament defeats its 
own purpose if it leads to short circuit failures or early burnouts. Prog- 
ress in any business is limited at best by the average product ob- 
tainable under the best practical conditions of manufacture for that 
period. Fortunately, best practical conditions of manufacture im- 
prove, but new designs must keep step with manufacturing skill. 

Fig. 8. — Life Test Equipment 

The diversity of types of lamps which are required for projection 
lamp service is a factor which causes production on an}^ one type to be 
small. At present projection lamps are made in voltages from 6 to 
250, in wattages from 15 to 30,000, in tubular, round and pearshape 
bulbs of various sizes, with different filament constructions, 
with different light centers, with different bases, with different ratings 
for life, and with different bulb materials. Manufacturing a few 
special lamps of a type is expensive because equipment must be 
changed and adjusted for every order. This changing increases oppor- 
tunity for error and spoilage in manufacture. Standardization of 
types is essential for low cost. 

The present trend is to distinguish further between the demand 
for maximum illumination and the demand for longer life on con- 
centrated filament lamps. Round bulb lamps for spot light and com- 
mercial installations are to be increased in life. Tubular lamps with 
monoplane filaments are to have reduced life because this seems the 
best way to give the customer what he wants in the way of better 


Dr. Story: Was I right in understanding that the gas filled 
lamps were never exhausted but simply rinsed out with the final gas? 

Mr. Burnap: The lamps are not completely exhausted; they are 
partially exhausted and refilled with dry inert gas several times. The 
process is a rinsing process where the injurious oxygen and water 
vapor are removed by successive dilutions with dry inert gas. Gener- 
ally the wash gas is not the same as the final filling gas. Lamps are 
washed out with nitrogen but are usually filled with argon because 
argon gives better lamp performance. 

The wash process can be used only for gas filled lamps. It is 
not suitable for vacuum lamps. 



By Feank Benford* 

The theory of illumination between two parallel planes was used by Nutting 
in the development of his refiectometer, but the de\dations of the instrument 
from the simple theory were so large as to destroy its usefulness. It is an instru- 
ment of the greatest simphcity and durabihty and is ideal where portability is 
desired. The present refiectometer, which is wedge shaped, is the result of a 
series of investigations looking to an instrument of good accuracy and at the 
same time maintaining the extreme simphcity and durabihty of the older instru- 
ment. The theory of illumination by a Hmited plane is touched on, and some of 
the details of specular refiection are examined. One form of a wedge refiectometer 
has been specially designed for direct vision, and has good accuracy for the 
particular angle of view fixed by the construction of the instrument. The second 
form of the instrument reads in a manner that is independent of the process of 
refiection and therefore gives accurate results for all types of diffuse or specular 


THE search for simpler and more accurate photometric instru- 
ments has nowhere been more keen than in the particular case 

of instruments to measure the coefficient of reflection of light re- 
flecting surfaces. There are a number of instruments now available 
for this purpose, and for laboratory service these seem to be entirely 
satisfactory, but there still exists a need for an instrument of simpler 
construction and one having a minimum of auxiliary parts. The 
Taylor refiectometer and the Karrer refiectometer are both examples 
of instruments of good precision and well suited for laboratory use 
and at the same time they have a large degree of portability so that 
they can be used on "location." The integrating sphere method 
developed by Mr. Little and the part-sphere method developed by 
the writer are strictly laboratory methods. The greatest degree of 
simplicity previously attained was in the Nutting refiectometer, 
which instrument is unfortunately marred by inherent errors of such 
size as to render the instrument totally unreliable, for as will be shown 
later, the indications of the instrument scale are infiuenced by factors 
that are in general of an unknown size and therefore it is not possible 
to correct the readings by a calibration curve. 

The instrument herein described has been under development 
for several years and it has now reached the point where the essential 
simplicity of the Nutting instrument is retained and the accuracy 
is apparently of the same order as that of the more complicated 
laboratory instruments. A brief examination of the theory of re- 
flection is a necessary preliminary to an understanding of the details 

* Physicist Illuminating Engineering Laboratory, General Electric Co. 


102 Transactions of S.M.P.E., August 1925 

of the instrument, and this is best done by a re-examination of the 
theory of the Nutting reflectometer, and also a brief consideration 
of some available test data on various reflecting surfaces. 

The Nutting Reflectometer 

The Nutting reflectometer is based in theory upon the illumina- 
tion received by a surface set parallel to a uniformly luminous plane 
of infinite extent. It can be shown that the illuminated surface 
receives just as much light per square centimeter as is emitted from 
each square centimeter of the luminous plane or illuminator. It is 
assumed that the plane is of uniform brightness from all angles of 



/ T 


/ h 



F/a / 

view, that is, it is a perfect diffuser. In Fig. 1 let us assume that the 
point I is the central point of an infinite diffusing plane of brightness 
B candles. The illumination of the test point T is found as follows: 
The area of an elemental ring in the illuminator having I as a 
center is 

dA = 2Trh tan a da 

The illumination received at T is computed from the inverse square 
law and the cosine law applied to both surfaces. 

cos^ a 

dE = B dA 



E = 2irB S COS a sin a da foot-candles 

When a = 90 deg., that is, the illuminating plane is infinite in extent 

E = tB foot-candles 
and if the test surface is a diffuser with a coefficient K the intensity Bt 
of the- reflected light is 

Bt = KB candles per sq. it. 

Benford — A New Refledometer 


It will be noted that the separation, h, of the points I and T does not 
appear in the equation, showing that the illumination is not dependent 
upon the distance in this limiting case. For some particular limiting 
angle a 

Ea = irB sin^ a foot-candles 

This equation is of particular interest in connection with the 
analysis of the Nutting reflectometer as it makes possible a com- 
putation of one special case of great practical importance. The new 
instrument to be described later originated from a study of the older 
instrument and indeed some of its parts were taken to build up the 
experimental reflectometer. Therefore some further attention must 
be paid to the older instrument. 

The Nutting reflectometer is composed of a nickel band or ring 
7.25 inches in inside diameter and 1.65 inches high. The illuminating 
plane in this case is a disk 7.25 inches in diameter and separated 
from the test surface by 1.65 inches. In Fig. 2 the infinite plane is 

\ ^ 

/ /'A 

B \ 

1 I ^ } 

\ 1 

I A 






replaced by a disk A, whose edges viewed from the test point make 
an angle a with the axis. The walls of the ring being mirrored the 
disk can be seen reflected in them, and this reflection appears as an 
annular ring B placed about the disk A. Two reflections give another 
concentric ring, C, etc. and each ring is less bright by the quantity 

104 Tramactions of S.M.P.E., August 1925 

of light lost on each reflection. Calling the coefficient of the walk w, 
the illumination at T can be approximated by 
E = 27rBy^°cos X sin xdx 

-\-27rwB S^ COS X sin xdx 


-{-27rw^B S^ COS X sin xdx 


This series integrates to 

E — tB [sin'^a-^w {sin'^b — silica) -\-w^ (sm^c — siii^b)-\- . . . .] 
Measurements on the Nutting instrument gave 

Coefficient it; = 0.53 

a = 65° 33' 
6 = 81° 23' 
c = 84°48' 
and these substituted in the equation above gives: 
^ = 7rB [0.830+0.530 (0.977-0.830) + 0.281 (0.992-0.977)+ . . . .] 

= 0.9127r5. 
This instrument, therefore, has a correction factor of 0.91 for a 
perfect diffusing surface. This factor has been determined by an 
independent method* to be 0.90 as derived from the Nutting value 
of 0.88 for the coefficient of reflection of magnesium carbonate and 
the "part-sphere" value of 0.975 for the same material. The inter- 
ference of the end of the photometer which is inserted through the 
ring lowers the illumination at T slightly and the agreement between 
the computed factor of 0.91 and observed correction factors 0.90 
is as good as can be reasonably expected. 

A second special surface is a specular reflector which reflects 
light by the geometrical law ''the angle of reflection is equal to the 
angle of incidence." The Nutting reflectometer is so proportioned 
that when testing a mirror the entire quantity of light passing through 
the test side of the photometer field is reflected once from the nickel 
ring which in this particular instrument was found by test to have 
a coefficient of 0.53. This is shown in Fig. 3 where a ray is traced 
from a point I' (adjacent to the point I of the previous figures) to 
the ring at R, the specular surface at T and then into the photometer. 
The brightness of the illuminating plate may be taken as identical 
at I and V, but as the point I' is seen as reflected by the ring at R 
the apparent brightness will be 0.53 of its real value. Therefore, for 
specular surfaces, the instrument has a correction factor of 0.53. 
This reveals the weakness of this instrument because a great majority 
of all surfaces in which we are interested are mixed surfaces, re- 
flecting by a process that is a combination of regular reflection and 
diffusion, and therefore the correction factor lies at some unknown 
value between 0.90 and 0.53. The probability of large errors in this 

* Benford — An Absolute Method for Determining Coefficients of Diffuse 
Reflection. General Electric Review, January, 1920 — page 72. 

Benford — A New Refledometer 


instrument removes it from consideration as a working tool, and this 
is so generally recognized that it has fallen into disrepute. 

The photometer is of the polarization type and the indicated 
coefficients for one component of the light is 



F/Q. 3 


-K"i = tan^ s 
where s is the angle read on the pointer that rotates with one element 
of the polarizing system. To eliminate the effects of selective polarized 
reflection which occurs on every surface, the photometer is rotated 
through 180 degrees and a second photometric balance made, giving 

i^2 = COt2^ 

106 Transactions of S.M.P.E., August 1925 

where the angle t is read on the same scale as s, but it is over 45 deg. 
whereas s is always less than 45 deg. The indicated coefficient K 
is then 


Direct Vision Type of Wedge Reflectometer 

For many of the more ordinary mirror surfaces the laws of re- 
flection are known accurately and in great detail. Thus a single 
surface of glass with a refractive index of 1.52 reflects 4.25 per cent 
of the Hght incident at 90 deg. or normal incidence; at 30 deg. about 
5 per cent; at 60 deg. some 9 per cent is reflected and at 90 deg. or 
grazing incidence, the reflection is complete; that is, 100 per cent. 
It is thus obvious that we cannot observe a specular surface at one 
angle and determine its coefficient of reflection. "Coefficient of re- 
flection" ordinarily means the average coefficient without always 
being specific as to the conditions of illumination or observation . 

As an example the glass surface noted above would be found to 
reflect from 4.25 per cent to 100 per cent when placed horizontally 
under a uniformly bright sky and the angle of observation varied 
from deg. to 90 deg. but if a number of angles were observed and 
then due weight were given to each angle depending on the quantity 
of light received and reflected at that angle the average coefficient 
of reflection would be found to be 19 per cent. Viewed at an angle 
of 71 deg. the reading on the glass would be found to agree with the 
average, but this particular angle would probably not be correct for 
any other surface. 

A reflectometer, built in the form of a wedge, that is, having a 
dihedral angle between the diffusing plate and the test surface, is 
illustrated in Fig. 4. It was found that the "integration" of light 
was much more complete near the edge of the angle than it was 
near the back wall, and this has an interesting secondary effect. 
When the point B on a specular surface is viewed the point Ai on 
the diffusing plate is seen by reflection. But the point under direct 
observation on the diffusing plate was at A and its brightness was 
somewhat less than that of Ai. Therefore the comparison of the two 
fields gave a coefficient for the test surface that was higher than the 
true value. With the photometer drawn back to its limiting position 
the readings on a specular reflector could be increased several per 
cent, principally because A and Ai were more separated. With the 
photometer advanced so that A and Ai fell near the edge of the 
wedge the reading could be brought to within less than one per cent 
of the computed value. 

The calibration curve of Fig. 5 was made with the instrument 
arranged as for "direct vision"; that is, the test surface itself was 
viewed in the field. In order to reach the edge of the wedge without 

Benford—A New Refledometer 


using light at angles too close to grazing, the light was received through 
a pair of reflecting prisms as shown in Fig. 4. 

The calibration curve of Fig. 5 was made by observing the 
surface reflection from one, two, three and four pieces of cover glass. 
It was found that the instrument read within one per cent in all cases 
and an additional test on a mirror having a coefficient of 0.81 gave the 

Fig. 4 

same size error; the reading on magnesium carbonate was substan- 
tially exact. This form of instrument is therefore evidently well 
suited for a surface that diffuses the light perfectl}^ as does magnesium 
carbonate but unfortunately such surfaces are rare and furthermore 
they are not the surfaces in which engineers are most interested. 

The great majorit}^ of reflecting surfaces act by a mixture of 
specular and diffuse reflection and it is obvious that if one com- 


Transactions of S.M.P.E., August 1925 

ponent only, the diffuse one, can be measured accurately, and the 
specular component is measured with an unknown degree of error 

D//^£-cr i//s/orv h/eoo^ rv/^e 



\- eo 
)i 70 
% .GO 


































JO .ao .JO ^ .SD .(oo 70 .80 .so IC 



Fig. 5 

then the net result will be in error to a degree that is difficult to 
estimate and the value of all readings is open to suspicion. It was 
this state of affairs that led to the development of an altered form of 

Benford — A New Refledometer 


this instrument that escapes this limitation. This form of instrument 
is therefore well suited for mirrors and polished surfaces that are 
known to have fairly constant coefficients at angles not too close 

Fig. 6 

to the grazing angle, but for measuring those surfaces that require 
an averaging process another type of instrument is required. 


Transactions of S.M.P.E., August 1925 

The Target Type of Wedge Reflectometer 

In this instrument the idea of a nearly perfect integration of 
light was abandoned and the first purpose was to establish conditions 

IND/RECT \//S/0^ l^enc^E TYPf: 






,^ 0.70 

^ 0.40 






























a/0 0.20 0.30 0.40 0.50 0.(S0 0.70 0.80 0.90 /.6 


Fig. 7 

Benford — A New Reflectometer 111 

such that the instrument would give equal readings on equal surfaces 
absolutely regardless of how they differed in their proportions of 
specular and diffuse reflection. Also, it is essential to escape de- 
pendence upon the coefficient at some particular point on the surface. 
The obvious way to gain both these conditions is to view targets 
illuminated by the illuminating plate and the test surface. The 
instrument now takes the form illustrated in Fig. 6 where the targets, 
small ovals of rough ground porcelain, are supported on flat springs 
that press against the two surfaces. 

The theory of this instrument has not been completely worked 
out from the mathematical side and dependence has been placed 
on thirteen test surfaces, twelve of which have been tested by in- 
dependent methods at other laboratories. The agreement between 
laboratories was not all that might be desired; the results obtained 
by the writer with the Nutting instrument (modified for direct vision) 
being particularly out of agreement with the others, were not included 
in finding the averages. The results for each sample are therefore in 
doubt by about one per cent in all cases, but this accuracy is suffi- 
cient for the time being. 

The upper point on the curve of Fig. 7 is the reading on mag- 
nesium carbonate, and it is probably correct to within one-half per 
cent; also the lower point is the reading on the interior of a box 
lined with black felt and here also the error is hardly over one-half 
per cent. Between these two extremes the other points come fairly 
close to a smooth curve, but this agreement is not the important fact. 
The circles represent tests on diffusing surfaces while the stars 
represent tests on surfaces that have a strong specular action. 
There is no indication that the readings of the reflectometer are influenced 
by the character of the surface^ and this is the optical condition which 
has been sought by the writer for a number of years. 

The target type of wedge reflectometer may be summarized as 
follows : 

(1) Readings independent of specular or diffuse character of 
test surface. 

(2) Readings independent of mottled or uneven character of 
test surface. 

(3) The instrument is complete in itself and requires no auxiliary 
parts for its operation and is perfectly portable. 

(4) It can be made in a form permitting measurements on a 
wall or other flat surface. 

(5) The instrument can be built of materials that do not change 
with age and therefore it will stay in calibration. 


Dr. Story: Has a secondary screen been substituted for the 

Mr. Benford: Such targets are used in place of direct vision. 

Mr. Renwick: I am very pleased indeed to see an instrument 
which will give diffuse reflection coefficients so easily. I think it will 
be of value in determining the reflection coefficients of photographic 
materials, a matter which has been under discussion recently. 

Mr. Summers : Are the results with this instrument comparable 
with those of the sphere method used by Mr. Little? 

Mr. Benford: Yes. I have used Mr. Little's results for cali- 
bration as accurate standards to whichto work because they agreed 
with several other laboratories' results. 



By Wm. V. D. Kelley* 

DURING a luncheon at which several members of our Society 
were present, reference was made to a patent, that had recently 
been issued to me, and one of the party remarked that he was 
unable to understand the reason for the broad claims that had been 
allowed. In view of the great number of patents that have issued in 
this branch of photography, he is interested in knowning what lines 
of development are still open for improvements by inventors. I am 
also requested to enlighten the members as to the reason for the ap- 
parent similarity in many patients that have issued and if differences 
exist to point them out where possible. 

In the time available for searching patents it has been possible 
for me to make only a start and if time and health permit, the work 
will be completed as herein planned. 

Not being a patent attorney, nor an authority on patent matters, 
these comments are necessarily from the point of view of the appli- 
cant, who has gathered experience, if not much law. 

My conception of a patent in the United States, is any combina- 
tion of known or unknown elements, that when combined, produce a 
new result. As you cannot patent an idea, one is confined to the means 
or machinery or ingredients used in producing the new result. An 
apphcation usually begins with the words *'A new and useful improve- 
ment in." Inventions are mainly improvements. And you can see 
that an improvement may be a very minute change that turns failure 
into success. This limited demarkation between many patents or 
applications is quite noticeable in the field of Color Photography. 

Sometimes the incident seems of slight importance and the patent 
is limited in its scope and in its claims, but if this step or incident 
supplies the solution to the problem, then such a patent is of more 
value commercially than the one with broad claims. John K. Brach- 
vogel says in the Scientific American: "Now this is well illustrated 
by the instance of the Sillman-Picard-Ballot patent for a process of 
oil concentration of ores, which was extremely limited in that it 
covered merely a specific percentage of the oil used and which was 
regarded by most patent attorneys as invalid for that reason. Never- 
theless, because of the outstanding practical results accomplished by 
this patented process, the court upheld the patent, with the result 
that its owners were paid many millions of dollars for the use of the 

Samuel Cox, of England, English patent No. 15,648 of 1914 
patented the idea of producing a blue tone image in a film, then sen- 

* Kelley Color Laboratory Inc., Palisade ..... N. J. 


114 Transactions of S.M.P.E., August 1925 

sitizing the gelatine stratum with bichromate, a light sensitive salt, 
printing under a positive and finally dyeing the second image with 
Red dye, using the Pinatype principle. I took out a patent in this 
country for the same kind of article, wherein the first image was DYE- 
TONED and the second image produced as Cox describes. (U. S. Pat. 
No. 1,278,161, Sept. 10, 1918). The difference being that, in the 
former, a picture was produced by the use of a salt of a metal, while 
the latter uses the principle of converting the silver image to a mor- 
dant and was dye-toned. F. E. Ives, U. S. Pat. No. 1,170,540, Feb. 
8th., 1916 also describes a blue tone for the base image and a Pinatype 
for the second image. This patent to Mr. Ives was applied for July 1, 
1914 and while it is the same as the Cox invention, the Cox Patent 
was not a reference against Ives. The three following patents were 
co-pending at the Patent Office and it will take a Phildaelphia Lawyer 
to determine which one of the inventors was the true inventor of 
certain features which are common to the three patents and there is 
further doubt as to whether the common features were new to either. 
One claim from each patent is below: 

FOX #1, 166, 125. Dec. 28, 1915. 

CLAIM: "A photographic process involving the production of a negative of two 
images one taken through a red filter and the other through a green filter, im- 
printing the first mentioned of said images upon transparent or translucent 
sensitive material, coloring said image bluish green, imprinting the other of said 
images upon said material in registry with the first image imprinted thereon, 
and imparting to said second image, by the use of a basic dye, a red color, sub- 
stantially as set forth." 
IVES, #1, 170, 540. Feb. 8, 1916. 

CLAIM 12: "A color photograph or color motion picture filni comprising a 
colloid layer upon a suitable carrj-ing base and containing in said layer an in- 
soluble color photographic image, and also in registry therewith an image of 
soluable dye-stuff of a different color." 
FOX, #1, 207, 527. Dec. 5, 1916. 

CLAIM 1: "A photographic process comprising the production of two negative 
images one taken through a green filter and one through a red filter, imprinting 
one of said images upon fight transmitting material, coated mth a sensitive 
emulsion, toning the print to a color complementary to that of the screen through 
which the corresponding negative was taken, imprinting the other of said images 
on said material in registry with the first image imprinted thereon, and coloring 
the second image a color complementary to that of the screen through which 
its negative was taken, substantially as set forth." 

There is a difference in the above patents and this difference may 
or may not make the particular invention the one that will become 
of greatest value. Time tells that part of the story. It is probable that 
the courts will not be called upon to settle the questions that are con- 
fusing in these cases. If we follow the work of the inventor we can 
determine, sometimes, the direction in which he is moving. 

The growth in an art in the hands of an individual may be fol- 
lowed from the patent office records. The Examiners are guided, very 
likely, by their familiarity with pending cases. Take the case of 
Mr. Ives, as an example. 

Kelleij — Color Photography Patents 115 

=1,170,540: Blue tones the first image and resensitizes T\'ith bichromate. 
^1,207,527: " " " " " " " " iron. 

=1,278,668: " " " " " " uses the original silver. 

=1,499,930: Same as last. 
f 1,538,816: Same. 

Confusion arises but rarely from having the cases filed in a divi- 
sion other than the one to which it should properly be assigned. I 
believe the following to be true but have not actually checked the 

A method for treating strips of films or ribbons was filed in the 
Photographic Division and the patent granted. Another inventor 
filed his case in the division that handles papers and the case was 
apparently handled as a method for treating wall papers and a patent 
was granted. The Examiner that cared for the first case made sure of 
the invenion by having the Office send him to the manufacturers 
plant and examine the device in operation. Years afterward he was 
unaware that a patent for substantiahy the same device had been 
is.sued in another division of the Office. 

The difficulty of understanding some of these color patents 
may be gathered from these quotations of a report made by a trained 
patent attorney. 

It is possible to read this claim so as to require the formation and coloring 
of one image before the other is formed and colored, and if so construed, the B 
patent would not infringe, and, if not so construed then it is beheved that the 
claim is invahd in \'iew of the article in the B. J. of Photography under date of 
Jan. 5, 1912. 

Claims X and X fall in the same category. That is to say, they are appar- 
ently prima facie infringed by B, but are susceptible of a narrower interpretation, 
in which event B would not infringe, but, if construed broadly they are anticipated 
by the article above referred to. 

Of such details are patents made. 

It has been said that all that a patent amounts to is a chance in a 
law suit. A patent does more than that. It fixes a date. It is an 
historical record. It is a notice to the World to beware. It may be- 
come of great value in the event some incident in the case develops 
into great commercial value. The inventor files his case, I think, more 
to establish his dates, than for the immediate protection. Inventions 
and the filing of Patent Applications usually precede the Commercial 
development . 

We will now make an invention and see how it works. 

Start with double coated film. Print an image on each side. The 
developed images to be negative. The images are bleached in a bath 
that hardens the gelatine in the vicinity of the silver and leaves the 
balance of the gelatine softer than the image portions. Fix the film 
and dry it. Xow bathe in a water bath containing Congo Red dye. 
Dr}^ and pass the side representing the Red negative over a roller that 
will apply a dilute solution of acid to one side only. The Red dye will 
turn Green. Dry and project. 

116 Transactions of S.M.P.E., August 1925 

Double coated films are old and were described in the Goodwin 
patent. Use a bleach as described in Capstaff No. 1,315,464 (U. S. 
1919) and if Kodak object, then use any one of similar bleaches that 
give similar results. 

The idea of treating two sides to one color and then converting 
one side to a complementary color is old. It has also been patented 
by Fox. So you can call it new if you like. It is all the same for the 
purpose that I have in mind. No one, to my knowledge, has printed 
prior to two years from this date, the fact that a dye can be used in 
this conversion scheme. This is the new element in the combination 
that breathes life into this application. We have a good chance for 
the patent and if filed it may be granted. 

Let us suppose the patent has been granted. 

We now have the patent but cannot use it for we may find that 
there is a dominating patent already issued. If the Fox patent broadly 
covers the idea of applying the same color to two sides of a film and 
then altering one of them chemically, to a complementary color, we 
might be in this position : — Fox could not use our invention and we 
could not make use of our own invention without permission from 
Fox or his assigns. 

A similar case is that of Ives and Crabtree and the copper 
mordant cases. Crabtree has the dominating case. Ives covered 
natural color positives so thoroughly that Crabtree could nor use his 
invention for making certain kinds of color films while Ives could not 
make any of the films because of the dominating Crabtree invention. 
That is the situation as it appears to one standing on the side lines. 
Actually, the Eastman Company threw the Crabtree invention open 
to users of their raw stock. It appears that the use of copper ferro- 
cyanide as a mordant was not really new to either of the inventors, 
the facts having been discovered by Namias and the description 
buried in some out of the way place. 

One or more branches of the art will be discussed and briefed for 
future meetings. For this first paper I have covered DOUBLE 
COATED FILMS only and then only those for which patents have 

Class I — Double Coated Positives, Div. A 

1- Double coated Film. Goodwin Patent No. 610, 861. Sept. 13, 

2- French Pat. Gaumont No. 420,163 — Stereoscopic Pictures. 
Filed Nov. 15, 1909. Granted Nov. 16, 1910. 

Published Jan. 24th. 1911. 

Invention :-' 'The toning or dyeing in colors is to be affected on 
each face in two different colors which may be chosen almost comple- 
mentary (for example, green and red). 

CLAIM :-This invention comprises essentially the use of a film 
printed on its two sides, each of its faces dyed or toned in different 
colors, for Kinematographic views in relief. 

Kelley — Color Photography Patents 117 

Hernandez-Mejia claimed that he made his invention prior to 
Nov. 16th. 1910 effective on that date, which is the date of deUvery. 

The U. S. Patent Office in their letter of Sept., 1915, withdrew 
this Gaumont patent as a reference. 

3- EngUsh Patent No. 24, 534 of 1912. to John E. Thornton. 
Apphcation filed Oct. 26th. 1912. 

Accepted Oct. 23rd. 1913. 

Claim 1- In the production of kinematographic color films pre- 
paring from a single alternative negative of sectional color pictures 
two or more negatives of consecutive pictures each negative being of 
one color and subsequently preparing the final color film for pro- 
jection substantially as described. 

4- U. S. Pat. No. 1,245,822 Nov. 6th. 1917. John E, Thornton. 
Filed June 7th. 1913. 

Corresponds to English 24, 534 of 1912. 

Specification says:- 

A- Its black image may be toned, one side to an orange-red, the 
other to a blue-green color. 

B- The silver may be removed and replaced by dyes, by one of 
the well-known substitution methods; or converted into a salt which 
reacts as a mordant on dyes and precipitates them in situ. 

The film is coated or sensitized on both front and back faces, 
thus producing a duplex film, but between the central celluloid base 
"b" and one of the sensitized layers "a" (or it may be both if desired) 
a layer "c" of light obstructing material, such as water soluable dye 
in gelatine is applied. This color washes out during development, 
fixing and washing as described in my application filed on the 10th. of 
April 1913, Serial Number 760,200. 

Accuracy of register is secured by the perforations in the films 
and by the feed devices all being exceedingly accurate, etc. 

CLAIM 2 :-The herein described method of producing two-color 
value positive pictures for cinematographic films from a single strip 
of negative film having the picture negatives of different color values 
arranged in alternating sequence there on, which comprises printing 
on one side of a transparent film positive pictures from the picture 
negatives of one color value, and then printing in register on the op- 
posite side of the transparent film the positive pictures from the 
picture negative of the other color value, the negative film and posi- 
tive film being superimposed during said printing operations and the 
negative film being advanced twice the distance of the positive film 
between the printing of each picture, and subsequently coloring the 
pictures on the positive film in the correct color. 

5- English No. 9324 of 1912. Filed Apr. 19, 1912. John E. Thorn- 

Requires two negatives and light obstructing medium in film. 

Claim 1- In the production of Kinematographic color picture 

films printing simultaneously from two negatives on both sides of a 

118 Transactions of S.M.P.E., August 1925 

film prepared with an opaque or light obstructing layer between the 
sensitized layers. 

6- U. S. Patent No. 1,250,713 Filed Apr. 10, 1913. Patented 
Dec. 18, 1917. 

John E. Thornton, Inventor. 

Corresponds to EngHsh 9324 of 1912. 

7-U. S. Patent No. 1,174,144. Filed June 21st. 1912. A. Hernan- 

Patented March 7th. 1916. 

CLAIM 1- The improved process of making a colored photo- 
graphic transparency, for projection or viewing by direct or reflected 
light, which consists in simultaneously taking two negatives of the 
same subject, from the same point, respectively through screens of 
complementary colors, one of said negatives being directionally 
reversed with respect to the other printing from one of said negatives 
upon one side of a single transparent positive film, sensitized on both 
sides, and from the other of said negatives upon the opposite side 
of said positive film with the images in register, treating one side of 
the positive film so that the image thereon will appear in one color 
and treating the opposite side of said positive so that the correspond- 
ing image will appear in a complemetary color. 

8— Wm. Frances Fox (Natural Color Company) No. 1,207,527 
Filed June 23, 1914. 

Patented Dec. 5th, 1916. 

"These images are to be precisely superimposed upon the positive 
stock, either upon one side thereof or one upon each side thereof." 

9— U. S. Pat. 1,259,411. Mar. 12th, 1918. Filed July 26th, 1917. 

W. V. D. Kelley. 

CLAIM 18 — "A double coated perforated photographic trans- 
parency having a record on each side, each of said records being 
registered horizontally with a certain perforation as a standard, and 
vertically with a certain other perforation as a standard, the records 
on said sides being colored in different colors." 

10— U. S. No. 1,278,162. Sept. 10th, 1918. Filed Feb. 8th, 1917. 
W. V. D. Kelley. 

11— U. S. Pat. 1,337,775. Apr. 20th, 1910. Filed July 18th, 
1918. W. V. D. Kelley. 

#1,166,121 Dec. 28, 1915 Filed Mar. 11, 1914 W. F. Fox 

1,166,122 Dec. 28, 1915 " Mav 29, 1914 W. F. Fox 

1,187,421 June 13, 1916 " Dec. 17, 1913 W. F. Fox 

1,172,621 Feb. 22, 1916 " Dec. 3, 1912 T.A.Mills 

1,273,457 July 23, 1918 " Jan. 6, 1917 J. G. Capstaff 

Double Coated, Div. B 

U. S. No. 1,191,941, July 25th, 1916. Filed Feb. 11th, 1913. 
Percy D. Brewster. 

U. S. No. 1,145,968, July 13th, 1915. Filed July 1, 1913. P. D. 


Dr. Mees: I have long had on my conscience the job of pre- 
paring a resume of color photography patents but I know I shall never 
do it. The task is enormous, searching for each claim and putting 
them together is a colossal job. I have card indexes to all British and 
United States patents and will have photostat copies made for Mr. 
Kelley. They are not complete before 1912 except insofar as the 
records of the British Journal are complete. In 1907 they published 
a list of all patents up to that date. I have abstracted all the color 
photography patents since 1912. I suggest that Mr. Kelley does not 
give opinions on the validity of patents. That is a matter for the 
Supreme Court. 

President Jones : I think undoubtedly the consensus of opinion 
is that Mr. Kelley should continue this work on patents for our 
autumn meeting. I think, Mr. Kellej^, you have ample encourage- 

Mr. Kelley: There are many divisions besides the double 
coated films covered in this first paper such as cameras, printers, etc. 
Also, I can include many references. I talked to Mr. Wall some time 
ago, who has a very large collection of data on patents and references, 
and I am making use of some information that he supplied. He also 
called my attention to a publication printed by the New York Public 
Library which contains a list of literature on color photographic 
subjects only, aside from patents. It is a book of noble proportions 
and would seem to indicate considerable interest in this subject. I 
would like to take advantage of the offer made by Dr. Mees to have 
photostat copies made of the index cards of patents. 

Dr. Mees: All right, we will have this done. 


May 5, 1925 

THE Committee has been fortunate this year in procurmg a pro- 
gram of an unusually varied and interesting character, and we are 
glad to say that there appears to have been greater willingness on 
the part of those who have been approached to contribute to this con- 
vention than on previous occasions. Several very helpful suggestions 
for papers and authors were sent in by other members of the Society, 
but we would like to see this made a much more usual practice. As 
matters now stand, almost the entire burden of securing a satisfactory 
program rests upon the shoulders of two or three individuals, and it is 
manifestly impossible for them to know all the people in the motion 
picture industry who have material suitable for presentation to our 
Society. There is, therefore, considerable danger of too frequent 
harvesting of a small corner of the field. For the same reason, it is 
also highly desirable that the composition of this Committee should, 
in our opinion, be changed every year. 

We have kept a complete record of all those with whom we corre- 
sponded. We believe that this practice, if consistently followed, will 
materially lighten the labors of each succeeding Committee. 

In spite of our best endeavors, we were unable to procure manu- 
scripts of more than three of the papers submitted to this convention 
by the time specified, but we believe that it is a good thing to try to 
get them, as it undoubtedly has the effect of impressing upon the 
authors the need for preparing a paper in suflicient time. At the same 
time the neglect of authors to submit papers involves the risk that 
papers unsuitable for our Transactions may be submitted at the 
meeting and so give rise to dissatisfaction and the somewhat un- 
welcome duty of rejecting such a paper falls upon the Committee sub- 
sequently. We believe, however,that the practice which we have been 
following of notifying authors that papers which have not received 
the approval of the Papers Committee prior to the meeting will not be 
published if found unsuitable even though they may have been read 
before the Society should be strictly adhered to, as only in that way 
can the Society hope to maintain the quality of its publications at a 
high level. Fortunately, the occasions on which we have found it 
necessary to reject papers have been very few. 

May we say in conclusion that a great deal more might be done 
be the authors of papers after the convention to facilitate publication 
of the Transactions. In only too many cases the author desires to 
withhold the manuscript for further slight alterations or additions 
for a period varying from a few days to several weeks, and this in- 
evitably delays the publication of the next issue of the Transactions 
very seriously. The same remarks apply perhaps in even stronger 
measure to the correction of discussions and their editing for pub- 
lication. W^hile the majority of speakers return the slips bearing 
their remarks with reasonably promptitude, this is by no means 
always the case and in a few instances serious delay has been caused. 

F. F. Renwick 


It is with great regret to all that we learn from Mr. Ren wick 
that he is planning to return to England in the fall. He has, therefore, 
resigned from the office of Chairman of the Papers Committee. The 
Society is, however, fortunate in having Mr. J. I. Crabtree accept the 
office to fill out the unexpired term. 

The Society also regrets the resignation of Mr. Nixon as Chair- 
man of the Membership Committee but is again fortunate in having 
Mr. A. C. Dick in his stead. 


The following additions have been made to the Society Membership. 

Brenkert, ELiRL, M 

49 Cortland Ave., Detroit, Mich. 

Cook, Otto W. M 

Research Lab., Eastman Kodak Co., Roches- 
ter, N. Y. 

De Vault, Ralph P. M 

Acme Motion Picture Projector Co. 
W. Austin Ave., Chicago, 111. 


Gray, Arthur H. A 

Lancaster Theatre, Lancaster & Causeway 
Sts., Boston, Mass. 

Harrington, Thomas T. A 

2233 McKinley Ave., Berkeley, Cal. 

Jeffrey, Frederick A. A 
North St., Adelaide, South Australia 

Miller, Arthur P. A 

Rothaker Film Mfg. Co., 1339 Diversey 
Parkway, Chicago, 111. 

Raess, Henry F. 

Warner Research Lab., 461 Eighth Av«. 
New York City. 

Serruriee, Iwan, M 

2730 Maiden Lane, Altadena, Cal. 

Struble, Cornelius D. M 

108 West 18th St., Kansas City, Mo. 

Wyckoff, Alvin a 

Famous Players Lasky Corp., Astoria, L.I. 
N. Y. 

Transfer from Associate to Active Membership 

Alexander, Don M. M, Alexander Film Co., Denver, Col. 



Braun, Wm. T. M 

5S E. Washington St., Chicago, III. 

Briefer, Michael M 

Atlantic Gelatin Co., Woburn, Mass. 

Cameron, J. R. 

410 Sloan Bldg., Cleveland, Ohio. 

CuMMiNGS, John S. A 
Duplex Motion Picture Industries, Harris St. 
& Sherman Ave., Long Island City, N. Y. 

Hubbard, Wm. C. M 

111 W. 5th St., Plainfield, N. J. 

Hutchinson, Wm. M. 

Box 576 Sherman, California. 

McAuLEY, J. E. M 

McAuley Mfg. Co., 552 W. 
Chicago, 111. 

McGiNNis, F. J. A 

Box .541, Palm Beach, Fla. 



Mt RPHT. E. F. 

Palisade Film Lab., Linwood Ave., Fort Lee, 

Porter, E. M. M 

352 Argle Rd., Brooklyn, N. Y. 

Ransdell, Rus.sel R. 

5408 Pasex Boulevard, Kansas City, Mis- 

Raven, A. L. M 

Raven Screen Co., 1476 Broadway, New 
York, N. Y. 

RosEMAN, Earl W. 

City Club of New York, 55 West 44th St., 
New York City. 

Sloman, Chibi M. 

East 3000 Woodbridge St. Detroit, Michigan 

Victor, A. F. M 

242 W. 55th St., New York City. 






Officers, Committees 3-5 

Introduction. By Adolph Zukor 7 

Student Psychology and Motion Pictures in Education. By 

M. Briefer 9 

Infra-Red Photography in Motion Picture Work. By J. A. 

Ball 21 

Incandescent Tungsten Lamp Installation for Illuminating 

Color Motion Picture Studio. By Loyd A. Jones 25 

Machine Development of Negative and Positive Motion 

Picture Film. By Alfred B. Hitchins 46 

A Museum of Motion Picture History. By T. K. Peters .... 54 

What Happened in the Beginning. By F. H. Richardson ... 63 

Control of Series Arc Generator Sets. By J. H. Hertner .... 115 
Report of Standards and Nomenclature Committee and 

Discussion Thereon 127 

Report of Pubhcation Committee 145 

Convention Notice 148 

Advertisements 149 

Number Twenty-two 

MEETING OF MAY 18, 19, 20. 21, 1925 


Gl IB 

*" 1 

i i 







I Number Tzvent\-tivo 

MEETING OF MAY 18, 19, 20, 21, 1925 

=^ ' ■ " ' f= 'f= i r===i i l [=] 


Copyright, 1925, by 

Society of 

Motion Picture Engineers 

New York, N. Y. 

Papers or abstracts may be reprinted if credit is given to the Society of 
Motion Picture Engineers. 
' The Society is not responsible for the statements of its individual members. 



Vice-Preside? li 
P. M. Abbott 

J. A. Summers 


L. A. Jones 

L. C. Porter 

Board of Governors 
L. A. Jones 
L. C. Porter 
Wm. C. Hubbard 
J. A. Summers 
A. B. Hitchins 
J. C. Kroesen 
J. H. McNabb 
F. F. Renwick 
J. C. Ball 

A. F. Victor 

Wm. C. Hubbard 


J. A. Ball 
J. I. Crabtree 

J. G. Jones 

L. G. Moen 

J. C. Kroesen 


C. E. Egeler, Chairman 
P. R. Bassett 
Rowland Rogers 

Standards and Nomenclature 
L. C. Porter, Chairman 
Hermann Kellner 
F. F. Renwick 

J. C. Kroesen, Chairynan 
R. S. Peck 
Wm. Sistrom 

Wm. F. Little, Chairman 

Wm. T. Braun 

F. H. Richardson 

CM. Williamson 

J. A. Summers 

W. C. Hubbard 

R. J. Pomeroy 
L. C. Porter 

Geo. A. Blair, Chairman 
S. C. Rogers 
H. A. Campe 

Coast Section 
J. A. Ball, Chairman 
Wm. V. D. Kelley 
Wm. Sistrom 

W. R. Rothacker 

Geo. A. Mitchell 

J.H. McNabb 

A. C. Dick 
J. E. McAuley 

F. F. Renwick, Chairman 
J. A. Ball 
Herbert Griffin 

I. L. Nixon, Chairman 
Roger M. Hill 
Earl J. Dennison 
Wm. C. Kunzman 

M. W. Palmer 

W". W. Johnstone 
J. I. Crabtree 


Proctok, B. a. Rossman, Earl W. 

2955 Grand Concourse, City Club of New York, 55 West 44th St., 

New York City New York City 

Ransdell, Russel R. Sloman, Cheri, M. 

5408 Pasep Boulevard, Kansas City, Mo. East 3000 Woodbridge St., Detroit, Michigan 

Urban, Charles M. 
Urban-Kineto Corporation, 

Irvington-on-Hudson, New York 


By Adolph Zukor* 

IT SEEMS to me that the work of the motion picture engineers is 
significant of the change which has taken place in the picture 
industry in the last few years. 

In its early days the motion 
picture industry was a battle- 
field. The leaders of the industry 
were perforce absorbed in the 
industrial problems which this 
rapidly growing business pre- 
sented daily. They were pioneers 
and had to fight the pioneer's 
battles. However, the solution of 
these problems and the gradual 
sohdification of the industry 
have now made it possible for 
everybody concerned in its 
growth to devote his attention 
more and more to the great es- 
sential — the improvement of pic- 
tures themselves. 

And there has been great improvement. Never have the 
studios turned out such a consistently high grade product. Proud 
as we are of this improvement, we are equally proud of the fact 
that it has come entirely from within the industry. Our specialists, 
our technical men, our leaders both in the artistic and industrial 
development of the business, have been evolved directly out of the 
motion picture ranks. We in the picture business have been favored 
with a great deal of advice from people outside our business, but 
despite this almost universal desire to advise us, we have been 
obliged to depend upon ourselves for the development of men and 
means of improving our position. 

Thus, the technical advances in direction have been made by men 
who have grown up in the studio. Most of our great stars and leading 

Adolph Zukor 

* President, Famous Players-Lasky Corporation. 


8 Transactions of S.M.P.E., September 1925 

players have received their training in pictures, alone. And now we 
have the author coming to our studios to learn the craft of picture 

Time was — and not so long ago— when a theatrical producer 
would not sell a play for picture purposes, when authors of reputation 
would not consent to have their writings screened. In a few swift 
years all that has been changed. Playwrights and novelists realize 
today the great advantages that accrue from having their plays trans- 
lated into pictures. Many of them have even gone beyond that; they 
are entering the studios and are learning how motion pictures are 
made and then are writing their stories directly for the screen. 

The result of this change of heart on the part of authors is that 
the screen has at its command today practically every novel, story 
or play of importance, in addition to the output of original stories 
written by men who have studied the technique of picture making. 

Of significance, too, is the definite effort being made to train 
people who can assume leadership in the various phases of this big 
business. For instance, in our own studio on Long Island, we have 
a class of twenty young men and women who are being taught the 
fundamentals of screen acting. These young people have been chosen 
after an exhaustive search throughout the country and represent the 
finest type of American youth. They will be given a course of six 
months' intensive instruction under conditions that no beginner in 
this business has ever before experienced. We are training young 
men in the business of selling these pictm-es and have already had 
three classes from which have been graduated young men who have 
found important places in our own sales organization. Before this 
magazine is published we shall have opened another school — for the 
training of theatre managers. These young men will be taught the 
most modern methods of presenting motion pictures to the public, 
so that the efforts of the people in the studio will reach the great 
multitude of motion picture theatres under the best advantages. 

So, you will see from all this that the leaders of the motion picture 
industry are alive to the possibilities of its future and are preparing 
m_an power to carry on the art and business of the motion picture to 
even greater heights. We have built a solid foundation, both financial 
and artistic, and this foundation is no less solid because it has been 
built through years of great stress and turmoil. Now we must erect 
the superstructure, and we have prepared for that task by developing 
the men and women who can do it. 


By M. Briefer* 

You must be cautioned in one respect. This study is neither 
technical nor academic — it is much too simple and prosaic for such 
ambitious designation. But, then, the subject is with the beginnings 
of intellect, and also, let us say, with a comparatively new form of 
education. By the very nature of these things, we are led into elemen- 
tary forms. 

In this outline, student psychology and educational motion 
pictures are considered not in specific terms, but rather in the broad 
application of the principles involved. The state of mind, its more 
appealing phases and general functions; the mental attitude of 
teacher toward student, and the place motion photography may 
hold in the educational field are presented in the narrative, rather 
than academic form. The discussion is predicated on the proposition 
that race progress is a mass movement with leaders and followers — a 
procession made up of rank and file marching together toward some 
goal not yet understood. The state of civilization as a whole, or that 
of any group or tribe, is generally not greater than the average of 
the individuals composing it. This immutable law of average is a 
wise provision, for while it exacts a price for the benefits of social 
intercourse, it delivers, in turn, ripe experience and priceless mental 
and spiritual gifts. 

Psychoanalysis has been practiced, in one form or another, from 
the moment mind became conscious of the existence of mind. To the 
modern psychologist, the study is a fascinating romance, and though 
still sparsely explored, it, like other branches of science, is slowly 
unfolding under pressure of intelligent research. The mechanics of 
the mental process is simple enough. We know it to be the storage 
place for information; that it is capable of registering impressions 
subject to association and recall. Registration, storage, association, 
and recall sum up the practical operations of the mind. We can pro- 
duce, mechanically, imitations of three of these four functions namely, 
registration, storage and recall, as in the phonograph record. The 
trouble begins with the association function, and is further compli- 
cated by the personal equation. 

* Powers Film Products, Incorporated, Rochester, New York. 

10 Transactions of S.M.P.E., September 1925 

The mind at birth is virtually a blank; so, to all intents and pur- 
poses, it is a clean slate upon which the world will write a life history, 
environment, trace a course, and shape a destiny. Every child is 
a dependent; subject to the vicissitudes of chance. The sublime 
theory of equal rights and equal opportunities is throttled in the 
very beginning. So it is, that by the time the child reaches school 
age, it is charged with many impressions, not attributable to choice; 
these may or may not serve as good foundations upon which to 
build. But whatever the impressions, it is a mistake to think of 
them as fixed or permanent. On the contrary, they are very transient 
and may, by suitable means, be easily displaced if necessary. Im- 
pressions become fixed, more or less, only after the faculty of asso- 
ciation has become strongly developed, and this faculty does not 
really begin to mature until the student is well advanced in school 
life. This is a happy circumstance, which the wise educator studies 
carefully, and takes advantage of at every favorable opportunity. 
With a little patience, we maj^ realize the psychical difference be- 
tween transient and fixed impressions from the following hypotheti- 
cal experiment. 

I take two disks, each about nine inches in diameter. One is 
colored red, the other blue. I say to the child, 'This disk is painted 
with a color and it is called red. This other disk is also painted with 
a color and it is called blue. If I mix the two colors beforehand, 
half and half, and paint with the mixture a third disk, the color 
will be violet." I have, as you perceive, given two correct impressions 
and one incorrect. But the child accepts all three impressions with 
equal confidence; it cannot mix colors in the brain; it does not try 
to reason the matter; it simply accepts the ideas provisionally. The 
red and blue impressions are truths, which the child will verify and 
fix permanently later on; but not until it has seen red and blue 
mixed, will it associate the two colors as combining to produce purple. 
The red and blue impressions, in the experiment, are primary sensa- 
tions which fact, however, has nothing to do with their being primary 
colors. The mixture of the two colors gives rise to a new sensation 
in which the component parts lose their individuality. If, instead of 
colors, we take two patterns, a circle and a triangle for example, 
and superpose them, we simply create a new design the component 
parts of which are as clearly individual as before. These examples 
are symbolic of the way in which ideas are built up in the brain. 
Fusion creates mental reactions with the development of new com- 

Motion Pictures in Education — Briefer 11 

positions. Combination is expressive of the association of ideas. 
Nature plays a simple harmony. In all her works, the same law- 
applies. Chemical substances react to form bodies differing from 
their component parts, and physical combinations, resulting in her 
splendid architecture. As the chemist and physicist perform their 
miracles of analysis and synthesis, so the psychologist, by means of 
the same general formulae, directs his research into that mysterious 
complex, the human mind. 

But I have led you away from our transient impressions. By a 
wise provision of the intellect, the most important matters of the 
mind remain transient for the longest time, and far into the evening of 
life they persist. In scientific thought, they have come to be known 
as theories. In ordinary language, the idea is expressed as conserva- 
tism. The fact that students are thus "open minded" would make 
their education a simple and sure process amenable to any well-ordered 
plan, were it not for a very disturbing element. In fact, your own 
impressions of what has been said so far must be, at least in part, in a 
very transient state; for with respect to the virgin field, which the 
mind presents at birth, only the half truth has been told. 

Within the span of one lifetime is experienced, in rapid succession, 
the entire development of the human race. We meet it at birth with 
the dawn of mind; but back of that, in the profound mysterious pre- 
natal state, we pass through even that remote period when all life 
was aquatic life with the earth still unprepared to receive it. This 
is the uncertain element; this period over which no human power ex- 
cept the parent has control. Thus, the mind dawns upon the world 
already armed with primal instincts and it is with them we have to 
reckon most profoundly, for whatever be the sensations or impressions 
that stimulate these primal instincts, they are, unfortunately, not 
of the transient variety. 

When a child is frightened into obedience or for whatever cause, 
when it is threatened with punishment for reasons it cannot under- 
stand, the instinct of self-preservation is powerfully excited. Fear and 
self-defense are the reacting elements. Cowardice and evasion are 
the reactions, and the quality and sum of the consequences are in 
proportion to the degree and frequency of the excitations. These 
early impressions are almost always permanent and strongly influ- 
ence each step in the subsequent training of the individual. Only 
an overpowering counter excitement can make a coward brave, or 
a liar truthful; wherein lies the hope of reformation and restoration 
through suggestive psychology. 

12 Transactions of S.M.P.E., September 1925 

We cannot attempt a discussion of the effects of heredity on 
human development except to say, that the specialists in that branch 
of study attach an importance to it entirely unwarranted by experi- 
ence. Heredity effects are insignificant as compared with the effects 
produced by the state of mind, the environment, the physical con- 
dition and general conduct of the prospective parent. Some day, 
it will be considered wise and expedient to require a compulsory 
report of expectancy, and attendance of special classes so that 
the education of children will begin at the beginning, and not at 
the parting of the ways. It is fair to assume that motion photography 
will have its full share in this form of education. Meanwhile, we 
must find how best to meet the needs of the moment. 

Credit is due to the pioneers in the field of educational motion 
pictures. It is admittedly a difficult task; but much experimental 
work and many disappointments may be avoided by taking a careful 
inventory of the material with which we have to do. This amounts 
to an analysis of the student mind, the teacher's treatment of it, 
the kind and type of motion pictures used and the manner of their 
presentation. Naturally, these elements apply relatively to all forms 
of education; with motion pictures, howeyer, they seem of much 
greater importance. In this connection, attention is directed to 
the splendid paper, 'The Use of Motion Pictures in Education" 
by Mr. F. N. Freeman, read before this society, and published in 
number twenty of the Transactions. Of special note also, is Mr. 
Rowland Rogers' breezy, statistical contribution, "Pedagogical 
Motion Pictures" published in number fourteen, S.M.P.E. Trans- 
actions. These men have analyzed the subject from many practical 
and psychological angles, in a really noteworthy manner. 

It is axiomatic that the most important attributes of the mind 
are the powers of concentration and imagination The first tends 
to fix independent impressions and store them in orderly manner 
for ready reference; the second, to relate and combine them in the 
form of complete and appropriate mental images. Concentration is 
concerned simply with the immediate present; imagination with anti- 
quity and the remote future and with all that may bridge these ex- 
tremes. There is no limit to the imagination. It is the seat of dis- 
covery and invention, of inspiration, culture, faith and spiritual 
being. You scientists and engineers know that theories are but 
mental images built from fragments of material stored in the sub- 
conscious, and the psychologist tells us that a criminal act is the 
result of a deranged mental system, or a partial or total lack of 

Motion Pictures in Education — Briefer 13 

imagination, or it may be uncontrolled imagination, run wild. A 
serious crime against society is seldom, if ever, committed when 
the mind is able to fully realize the consequences of the act. It 
seems highly important, therefore, to guard the gates of entry to 
the subconscious, for the conduct of the individual rests with this — 
he can make use only of that which is stored there. Civilization is 
teaching humanity a sense of its responsibility. Its tolerance has 
a wider scope. It embraces a broader vision. We have begun to 
question the wisdom of censuring too strongly the weak and mentally 
inefficient. Rather do we look to the system of education, the en- 
vironment, or what not, for the material these conditions have put 
at its disposal. It is, or should be, the business of motion photo- 
graphy to properly develop the powers of concentration and imagina- 
tion, and direct reason into normal channels. 

Psychology is not an exact science in the sense of being able to 
apply to it fixed laws or axioms. The complexity of the mental 
process does not permit of the strict isolation of its separate functions. 
The whole subject of mind study is a matter of careful deduction, 
but the science has so far progressed that we may lay down certain 
broad principles and arrive at a reasonably satisfactory classification. 
This is necessary if we are to adapt a course of study to the formative 
mentality, for the student, in his early period of mental digestion, 
may be led far afield in a direction wholly unsuspected, simply be- 
cause his concept ional powers have not been truly appraised. 

The foundation of knowledge is undoubtedly laid down during 
the first eighteen or twenty years, which time may be fairly divided 
into three distinct periods of about seven years each. During the 
best part of the first seven years the child is obsessed with intense 
curiosity. There appears little imagination. The child is essentially 
cruel and selfish. These qualities are clearly indicated from its 
treatment of small animals, its destructive tendencies, its desire 
to possess everything within reach and its anger when crossed. 
Everyone will probably subscribe to these terms except the mother. 
In the new brain cells, it will be remembered, is stored the age-old 
fundamental principle of self-preservation. Clearly this new human 
being, new at least to our understanding, must be carefully reared 
during these critical years. The child must be taught confidence; 
in a measure also, self-sacrifice; its demands should be satisfied with 
sound examples and, above all, it should find truth in everything 
it absorbs from its elders. Curiosity being the child's predominant 
mental phase, it cannot associate ideas effectively, and we thus find 

14 Transactions of S.M.P.E., September 1925 

it necessary to formulate studies based upon abstract impressions, 
the best of which are those which amuse and please and impose no 
mental strain. In some such way as this, the very important quality, 
that of good nature, is developed. 

The second period of seven years is more hopeful if our child has 
already had the right beginning. Here we find growing the seeds 
we have sown. Curiosity, while still a prime factor, is tempered 
with a striking ability to associate ideas. We begin to note the power 
of the mind for deduction. The early impressions, conceived in the 
abstract, are pieced together with the exercise of reason. The student 
displays a sense of mental balance and co-ordination. As a matter of 
fact, this is the real formative period of mental development; the 
preparatory stage; the most impressionable, and undoubtedly, the 
one in which the die is cast. 

Students between the ages of about seven and_fourteen are real 
problems. They are neither here nor there, as it were; they do not 
seem to fit altogether into the scheme of life as their elders under- 
stand it. We fondle and make foolish talk with babies, and we argue 
and attempt to reason with the older students, and find in both 
circumstances some measure of satisfaction; but with these of the 
second period we seem at a loss; and all because we make no real 
effort to live with them in their world. We expect these children 
to abide with us in our mental sphere, one which they have not yet 
perceived — do not in the least understand — while declining to share 
with them a mental state through which we have already voyaged and 
from which we have taken out full measure of experience. 

A common mistake of some educators lies in their expectation 
that these young students be contemplative; that they show respect 
and deference to a degree commensurate with the dignity and author- 
ity of the office of instructor, and clearly indicate their disappoint- 
ment when these expectations are not fully realized. Indeed, it is more 
than a mistake, for any display of impatience and distemper on the 
part of the teacher before these students destroys their faith and 
provokes an unwholesome state of resentment. There is no more 
effective method of sowing the seeds of hatred. 

Respect and admiration, like love and affection, are emotions. 
They cannot be taught as a language is taught. They cannot be 
commanded as a right or as a reward ; neither may they be invoked by 
coercion. They rise spontaneously in response to the right kind of 
conduct and performance. They are not conferred upon individuals, 
as such, but upon their deeds and ideals. When students show dis- 

Motion Pictures in Education— Briefer 15 

respect, it is invariable because their emotions have not been stim- 
ulated by the right attitude. Educators and parents alike have need 
to pocket their false pride, and strive to win, rather than command, 
these emotions. 

Motion photography is well adapted to this class of students. It 
should present happy and amusing situations, combining health edu- 
cation and simple truths. The morals should not obtrude themselves 
as deliberate lessons, but rather appeal as natural consequences of a 
set of conditions. Morals, truths, justice and consideration may be 
best taught as part of comedy and laughter, for these are, or should 
be, the child's happy, carefree years. These students should not be 
preached to, for such a course only leads to silent opposition. They 
will not accept, gracefully, the negative principle of teaching, ex- 
pressed by the admonition, "don't''; in fact, we carry with us, 
through life, a strong resentment to any form of prohibition which, 
after all, is but the challenge of human nature to interference with 
natural experiments in evolution. Perhaps, when the first worm 
ventured forth out of the soft ooze upon the freshly-formed earth 
crust, its mother worm said, "Don't go out there child, its dangerous!" 
And perhaps the baby worm replied in effect, "Mind your own busi- 
ness, mother dear, this is my experiment." 

The student of the second period is a large responsibility. It is 
rounding the first real milestone of life — the critical stage of sex ap- 
preciation, a flame which may cleanse or consume. It is strange 
how tenaciously we cling to our antipathy with respect to the bi- 
ological facts of life, permitting our children to discover for them- 
selves, in any old way, matters relating to the most vital and pro- 
found decree of nature. Without condoning the grossly obscene, 
it is safe to say that the so-called immoral plays and immoral pic- 
tures are doing more to banish evil than all the professional reform 
elements combined. Motion pictures do not attempt to smother 
truth ; they reveal it. Truth can never be immoral except as a state 
of mind. What is today a cautious whisper, tomorrow becomes a 
topic of intelligent discourse. Motion photography has done much 
already to reveal the truth about human conduct and sex relations. 
With special direction and efficient organization, an important study 
course can be developed, doing for the young that which their parents 
should, but don't. 

There is, perhaps, no more interesting state of mind than that 
found in the average student of the third period. At least the pos- 
sibilities are inviting. The susceptibility of this class to suggestion is 

16 Transactions of S.M.P.E., September 1925 

very noticeable : at the same time it is very keen to detect sham and 
insincerity, and whether we teach with pictures or textbooks, or 
both, it is important how the instructor deports himself before this 
body of students, for it is a critical body, naturally inclined to ques- 
tion. Curiosity has changed to inquisitiveness. The peculiar interest 
which attaches to these students rests with the fact that they repre- 
sent the age which will pass judgment upon our accomplishments, 
as we pass judgment upon those of past generations. It is that 
posterity of which we strive to merit approval, and all our hopes for 
the future are bound up in its success. Each teacher will make the 
task easier for the next and help himself also if he will just shed his 
years, enter into the spirit of youth, and be as much a part of the 
student body as the students themselves. 

Motion photography has the advantage of being impersonal. 
It never tires, never loses its poise. What it wishes to say can be 
well debated beforehand, and if perchance, it develops shortcomings 
and requires revision, there is no personal reflection involved, no 
feelings hurt, no serious loss of prestige. 

All knowledge is acquired and made of permanent value by 
repetition. Perhaps one of the most difficult things to do is to con- 
struct a picture that will bear repeated screening and still hold the 
interest of the student. An inviting possibility is to provide a 
number of brief texts enabling the instructor to emphasize before- 
hand some special feature of the picture for each showing, subordi- 
nating the others as completely as possible by suggestion. A picture 
will thus display a fresh element with each exhibition, and so fix the 
separate parts, first independently, and later as a complete whole. 
To show how such a plan would work out, a growing plant may 
serve as an example. 

It will help to improve the interest, faith, and appreciation of 
students if they are made familiar with the fundamentals governing 
the production of motion pictures. They should know, as far as possi- 
ble, the true relation of motion photography to natural phenomenon. 
The mystery of acceleration and retardation of motion, its apparent, 
not real, continuity upon the screen together with other essentials, 
should be carefully explained, lest speculation be aroused at the ex- 
pense of attention. On this assumption we may proceed to project 
the growing plant for study. If now, the instructor will stress the ap- 
parent rapid growth of the plant in the picture, with its slow rate in 
nature, the suggestion will fix the student mind on the physical dev- 
elopment of the plant while the imagination plays with the marvel of 

Motion Pictures in Education — Briefer 17 

speeding up nature's slow motion — condensing, as it were, the passing 
of time, correspondingly increasing the rate of movement in space; a 
simple illustration of the relativity of tune and velocity. The lesson 
has impressed the form of the plant during its various stages of de- 
velopment in a striking manner, and the student has probably ac- 
cepted the suggestion, and missed the other details. Speeding up and 
slowing down motion furnishes an infinite variety of possibilities. The 
picture maj^ be shown again, this time emphasizing the remarkable 
development of the large arteries which, as in the human system, pro- 
vide the means for circulating the chlorophyl, the plant blood, through 
the plant body. The student is again compelled, by suggestion, to 
focus attention on a particular phase of plant structure, and while 
the earher lesson of plant gro\^'th and its physical form will be ment- 
ally followed through this second screening, the main attention 
will be for the new idea; in fact, the two lessons will fuse. Plant 
structure, the dimensions relative to other plants, the^blossoms, 
the fruit or flower, each in turn can, by proper suggestion, be made 
as separate and distinct a study as is to be found in any text book, 
and infinitely more interesting. 

The example given above represents the idea, not necessarily 
the procedure. ^Mathematics will yield to the magic of the camera, 
especially in dealing with geometric forms. From the simple figures, 
the complex may be built up developing the problem graphically. 
Reversing the film, and the system is analyzed while again resolved 
into its simple elements. Botany, zoolog}^, biology, much of chem- 
istry and physics, many phases of engineering, mechanical operations 
and industrial process may be advantageously presented in a manner 
similar to the one described. In medicine and surgery, the records 
with motion photography are invaluable. 

In planning educational pictures the manner of showing them 
will, of com'se, be taken into account. Explanatory titles, if used at 
all, should not be painfully exact. The effect is enormously heightened 
when the right elements are left to the imagination. Details are 
wearying. The mind wishes to be left alone to work out its own unages, 
each one in its own particular way, and, as far as possible, this free- 
dom should be encom^aged. Given the fundamentals, with just 
sufficient detail to illuminate them, the mind will "see" and remem- 
ber, the more clearh^, because it is called upon to exercise the ap- 
propriate function. 

The faculty to observe, and the power to concentrate go hand in 
hand. Educators have long known that, as a general rule, the Intel- 

18 Transactions of S.M.P.E., September 1925 

ligence, and hence the class standing of students, varies as their 
power of concentration. When a number of people witness an exciting 
event, it is rarely that two descriptions of it are alike in every par- 
ticular. Frequently, they differ in the most grotesque manner. The 
fact is so well recognized that it may be dismissed with the mere men- 
tion of it; yet all co-ordinate thinking depends upon the accuracy of 
observation, which, in turn, is a function of concentration. 

It may at first appear that concentration predicates oblivion to 
all surroundings except the subject under immediate attention. This 
is not strictly so unless we associate concentration with absent mind- 
edness, as in the case of the old professor, slowly homeward bound, 
thoughtfully pondering a deep problem, who meets his own son with 
this greeting, ''Hello George! how's your father?'" One may be deeply 
engrossed with a particular matter, and yet be alive and alert, or, one 
may easily concentrate on a number of subjects in very rapid suc- 
cession. My wife, for example, apparently just glances at another 
woman, and later gives me a most minute description of her costume, 
from the shape and colors of her hat, to the design of her shoes. How- 
ever, omitting any further reference to the filial complex, it is to be 
noted that what we call observation cannot stand alone. Merely to 
observe means nothing. To fix the thing observed, complete in every 
detail, is the basis of memory and the foundation of experience. 
Children first learning to read piece words together by laboriously 
studying each letter. In the course of time, they learn to read the 
words complete, paying little attention to the individual letters. 
Stenographers learn to write and read complete phrases — at least, 
they learn to write them. It is by no means uncommon to find people 
able to read at once whole sentences. It is said of the late Theodore 
Roosevelt that he read at a glance complete paragraphs. One news- 
paper had it as a complete magazine page and I have since been 
expecting to hear that he read a whole book at a glance without ever 
opening the cover. We do not term reading an act of observation, but, 
whether we observe word pictures or the real thing, the mental 
mechanism functions alike, except as we read the imagination has a 
little more work to do. Many people cannot remember what they 
have read, but they are the same who cannot recall what they have 
observed. Thus, we note that observation and concentration have no 
value except as they are associated in memory; so that it is well worth 
while to study the reactions to different methods of memory training ; 
nor,^ must we forget the danger of developing a encyclopedic mind; a 

Motion Pictures in Education — Briefer 19 

memory at the expense of reasoning power. One thing seems certain ; 
except with the very young, successful teaching must rest with 
definite association of ideas, each new phase linked with something 
pertinent that has already been mastered. Association is better than 
absent-minded concentration. Detached subjects are soon forgotten. 
Those who "crammed" for examinations will have no quarrel with 
this statement. 

I should feel now about in the position of the preacher, when, 
after the service was over, one of the parishioners remarked to 
another, "That was a good sermon, brother," "Yes," came the reply, 
"but he passed up so many good places to stop." I cannot resist the 
temptation in closing to make one appeal for simplicity. We have no 
right to burden those who come after us with unnecessary and useless 
labor in their effort to acquire an education. Before we have gone 
very far with educational motion pictures, we may well ponder the 
question of teaching through the path of least resistance and by 
means of the simplest terms. It is bad enough to struggle with long 
tons and short tons, pounds, ounces, grains, scruples, pennyweights; 
avoirdupois, apothecary, and troy weights; pints, quarts and gallons 
(although pints and quarts belong rather to a secret language now) 
inches, rods, feet and what not; a ship travels so many knots and a 
railway train so many miles, while a horse is so many hands high, and 
a man so many feet tall. The whole mess is too many fathoms deep. 
All that is, indeed, bad enough without being] obliged to rummage 
through the ashes of dead languages to find what science has to say of 
its great achievements. If it were not for the popular interpretations 
given by newspapers and periodicals, the patient labor of scientific 
investigators, throughout the world, would be about 90 per cent good 
for nothing so far as service to mankind is concerned. Such is the 
history and fate of the stupendous volumes, conceived in impossible 
language, vainly appeahng to be liberated from their cobwebbed 
prisons, in remote corners of places where such books usually hiber- 
nate. Ten simple numerals will one day solve the riddle of the universe, 
and Brisbane says of the metric system that all the hard work there is 
in the use of it is to shift the decimal point about. Twenty-six simple 
letters are made to express every possible human emotion. Mathe- 
matics express every fact of natural laws; language expresses the 
whole of spiritual life. Why should we not make use of these two 
powerful instruments in the simplest and easiest way? 

20 Transactions of S.M.P.E., September 1925 

The ideal of education is, finally, the seeking after truth — to find 
the real purpose of life and to teach it. "We know not from whence we 
came, nor whither we go" nor, if we live but once, or whether our civi- 
lization is yet in the stage of short memory, to ripen and grow with the 
years, to remember the yesterdays — that our consciousness will, with 
the passing of time, come to know that a life is but as a day — to lay 
down the task and rest awhile, to reawaken with the dawn of another 
era. Whatever may be our belief, it is significant that within the 
heart of man, within the very core of his being, is an involuntary urge 
to do and to dare; to strive and to suffer; to hope and to pray for a 
posterity of which he has no conscious knowledge to ever have a 
part; yet, the urge persists, expressing in unmistakable language, 
man's destiny and fellowship with all that has ever been and will 
ever continue to be. In this task which is set before us, let there 
be truth in all things; in science, in ethics, in religion. "As we face 
the light, the shadows fall behind." Let us bring to these growing 
children the love of being; not the threat of retribution. Let us 
teach them to feel that their life is linked with the pleasure of work 
and service through all time, and that their less fortunate brothers 
will always have their chance ; that what we call death does not close 
the door forever to redemption. One life is not enough to merit the 
heavenly bliss held out to us in theology, and I like it not that hell 
is the alternative. We no longer torture the product of man's mind 
as for witchcraft; neither shall we oppress with fear. 

Man is the greatest miracle we know, 

All elements combining from his birth, 

With water, air and fire, and parts of earth 

Blending in perfect harmony to grow. 

He claims a kinship also with the sky. 

His heart is made of star-dust, and his dreams, 

Are shreds of moonlight, purest silver beams 

Falling from out that shining glow so high. 

Where then is born our widsom and our love. 

Our faith for sacrifice, our hopes so fair? 

Surely in some planet far above 

The northern star that lights the midnight air. 

Man is a part of all things that may be 

One with the earth and sky, the stars and sea. 

MuRiAL Brewster 


J. A. Ball* 

Photographs by infra-red light were first made some years ago 
by Professor R. W. Wood, of Johns Hopkins University. He noted 
that the most striking features of these pictures were that blue skies 
were rendered very dark, whereas green foliage was rendered very 
light. Photographs by infra-red light with these characteristics have 
remained more or less of a scientific curiosity every since. In Pro- 
fessor Wood's day the available photographic sensitivity in the infra- 
red was very low and the required exposure very long; furthermore, 
no one had pointed out a practical use for this effect. More recently 
Haller has announced an infra-red sensitizer which gives considerably 
increased speed and this, in combination with the Technicolor film 
sensitizing technique, has made possible a film sensitized in the 
infra-red which can be produced uniformly and economically in any 
quantity, large or small, and of sufficient speed to allow of good 
exposures in motion picture work. 

I am not aware that anyone has previously noted that these 
characteristics of infra-red photography — namely, to make blue sky 
dark and to make green foliage light — are just what are needed to 
make moonlight effects without the aid of artificial light. Such effects 
are of considerable importance in motion picture work. 

An approach to such effects can be made by taking scenes with 
visible red light, as, for example, a panchromatic film and an "A" 
filter and, in fact, such effects are commonly used nowadays. But 
the effects obtained by the use of infra-red light are far superior. To 
be sure a panchromatic film and a red filter make a blue sky some- 
what dark, but there is no brightening of the foliage; in fact, the 
foliage also is darkened. In using infra-red light, however, the sky 
is made still darker and the foliage is made quite bright, greatly 
enhancing the effect of a scene illuminated by a bright moon. This 
latter effect may perhaps find its explanation in the fact that the 
sensitivity of the eye, when adapted to moonlight intensities, has its 
maximum shifted towards the blue-green. Probably for the very same 

* Technicolor Motion Picture Corporation, Hollywood, California. 



Transactions of S.M.P.E., September 1925 

fundamental reason it has become customary to print up scenes for 
night effects with a blue-green or blue tint over all. When all these 
effects are combined, that is to say, when an infra red photograph is 
printed up with a moonlight tint, the effect is very striking. 

Some lantern slides have been prepared with clippings from 
motion picture film prepared in this way. In each lantern slide is 
shown the scene photographed in the ordinary way, side by side 

(a) Film sensitized in the ordinary 

(b) Film sensitized for improved 

with the same identical scene photographed at the same time by 
infra-red light. In these slides both types of scenes have a blue tint 
in order that in this case the comparisons shall show only the night 
effect created by the infra-red photography. Another slide has no 
comparative scene beside it, but is of interest in that it is a clipping 
from a scene taken for a recent production using film sensitized in 
the infra-red. The stars in the sky were, of course, double-exposed in. 

Infra- Red Photography — Ball 23 

A number of scenes in various productions have been photographed 
recently on this film. 

The lantern slides will demonstrate not only the general night 
effect, but will further show the enhanced cloud effects that can be 
obtained by infra-red photography. This in itself adds to the moon- 
light effect, because it makes white clouds stand out brilliantly just 
as they do on a bright moonlight night. In addition to that it is a 
valuable effect in itself, for oftentimes clouds are found against a 
hazy blue sky where the ordinary methods of correction are not 
powerful enough. The most extreme effects can then be obtained by 
infra-red photography. 

Besides the effects shown in these slides, there should be a num- 
ber of other effects obtainable by infra-red photography. For example, 
water is a powerful absorber of infra-red rays and the blue color of a 
large body of water is perhaps attributable to a powerful absorption 
which has its maximum in the infra-red. Night scenes on the water 
should be very effective where the blue and green tones of the water 
go dark, together with the sky, leaving reflections from wave tops, 
white caps, sails of a boat, etc., standing out just as they do in the 

The writer hopes at some future time to show some examples of 
this and other effects to supplement the examples shown herewith. 


Dr. Mees: I am glad that Mr. Ball has made pictures by infra- 
red light; I tried to do it about three years ago and failed. I thought 
that if I could take pictures at wave-length 750, the pictures would be 
of the type shown and give the moonlight effect. I tried to sensitize 
some film with kryptocyanine and got it fast enough to get still 
pictures by infra-red light, but I could not get enough sensitiveness 
in my film for motion pictures. The material sensitizes very strongly 
indeed, but at the point of maximum sensitiveness there are tremend- 
ous absorption bands due to the earth's atmosphere. Evidently Mr. 
Ball has succeeded where I failed — I could not get better than three 
pictures a second at f / 4.5. I imagine he has sensitized more efficient- 
ly. I wish he had told us how he did it but perhaps that is a trade 

Dr. Story: I should like to emphasize one point that Mr. Ball 
would probably have brought out more strongly if he had been here 

24 Transactions of S.M.P.E., September 1925 

to describe the stereopticon slides. Photographing by infra-red Hght 
does lower the value of the sky with respect to most other parts of the 
picture, since the sky diffuses to the camera relatively little of the 
light of longer wave-lengths. This lowering of the sky value gives, as 
the paper brings out, the general effect of moonlight. The point I 
wish to emphasize is that not OT\\.y is the average value of the rest of 
the picture raised relatively to the sky, but that the objects them- 
selves in general appear quite different. 

When photographing with infra-red the light from a blue sky 
has but little effect on the film, that is, all the effective illumination 
comes directly from the sun, or the light source is concentrated at 
one point. It occurs to me that this concentration of light source is 
the essential difference between moonlight and sunhght. The striking 
lack of half-tones in these stereopticon shdes made from the infra-red 
negatives would seem to furnish strong evidence for the belief that 
the effect of moonlight is produced largely by apparent contrast 
rather than by apparent intensity. I say "apparent" because the 
distribution of energy in the spectrum of the moon may be such as 
to give the sky the same relative energ\^ value as a clear sky by sun- 
hght. If this were true there might still be a greater apparent con- 
trast by moonlight due to its lower intensity. The half-tones might 
be too low in energy to affect the retina appreciably and so would be 
indistinguishable from the shadows. 

It would be interesting to have some further information on 
these points. 

Mr. Palmer: Can some one tell us what kind of filter you use 
in photographing with infra-red light? 

Dr. Mees: It doesn't matter, because the kryptocyanine has 
all its sensitiveness in the extreme red. If you cut out the blue with a 
yellow filter or a red filter such as 'Tricolor Red," the picture wiU be 
taken not by visible red light but by the extreme red. An}^ strong 
vellow filter will do. 




By Loyd a. Jones** 

The requirements of the illuminating equipment for use in 
studios where color motion pictures are to be made, are somewhat 
different than in the case of black and white work. The mercury 
vapor source, used so extensively in motion picture studios where 
black and white work is done, is practically useless for color work. 
The spectrum of this source is of the discontinuous or bright line 
type, and there are broad spectral regions in which no radiation is 
emitted. The satisfactory^ rendering of colored objects illuminated 
by this source is, therefore, quite hopeless. 

Electric arcs, especially the improved type such as the high 
intensity and white flame, are extremely efficient and produce light 
of very satisfactory^ quality. The illumination given is not as constant 
as is desirable, since all processes of color photography are especially 
sensitive to variations in exposure. Thej^ must be recarboned at 
frequent intervals and require attention during operation. For the 
general lighting, especially where it is desirable to support and man- 
ipulate the units from an overhead structure, they offer man}^ in- 

Tungsten incandescent lamps, even when operated at the highest 
practicable temperatures, are relatively inefficient. There is a rela- 
tiveh^ high proportion of radiation in the infra-red region thus giving 
rise to an uncomfortably high temperature when the required il- 
lumination levels are reached. Thej^ give ver}- constant illumination 
when operated at constant voltage, are clean and extremely con- 
venient to manipulate. 

^Mien it was decided to equip a color studio at the Eastman 
Theatre and School of Music, the question of the most suitable tj^pe 
of light source for color photography was given careful consideration, 
and after preliminary experimental work by Mr. J. G. Capstaff of 

* Communication Xo. 238 from the Research Laboratory of the Eastman 
Kodak Company. 

** Physicist Research Laboratory, Eastman Kodak Co., Rochester, X. Y. 


26 Transactions of S.M.P.E., September 1925 

this laboratory, who is in charge of the research work on color photo- 
graphy, it was decided to adopt the incandescent lamp as offering 
the most advantages with the fewest objections. 

Best size of unit. — During the experimental and development 
work done on the Kodachrome process for producing motion pictures 
in color, which has been in progress for several years, Mr. Capstaff 
has had extensive experience in using various types of tungsten 
incandescent lamps. Among these may be mentioned the thousand 
watt unit of the usual commercial type and a special 30 volt, 150- watt 
lamp of the locomotive headlight type. Lamps of the latter type were 
operated in groups of three connected in series. Such a group can be 
conveniently operated on a 110-volt line with a resistance, or in case 
of alternating current with a transformer, the best results being 
obtained by operating these at about 10 or 15 per cent above their 
rated voltage during the actual taking of the picture. They stood up 
very well under such over voltage conditions. They were used for the 
most part on relatively small sets and for this kind of work are as 
satisfactory as any type of lamp that has thus far been used. "When 
plans were begun for equiping a larger studio, however, it seemed 
desirable to adopt a somewhat larger unit in order that the number 
of units required should not be excessive. It was thought that a 
smaller number of relatively large lamps would be much more con- 
venient to manipulate in arranging the lighting of the sets and proba- 
bly would produce a somewhat better quality of lighting from the 
standpoint of distribution. 

Tests were made using 1,000-, 3,000-, 5,000-, and 10,000-watt 
units, some of which were made especially for us by the Harrison 
Lamp Works of the General Electric Company, and we wish to 
acknowledge our indebtedness to Mr. L. C. Porter and his staff of 
engineers for their assistancci and co-operation. The 3,000-watt unit 
was finally chosen as most nearly fulfilling all ]"equirements, although 
from certain standpoints a somewhat larger unit seemed desirable. 
The 3,000-watt unit was obtained in a P.S. 52 bulb, mogul screw 
base, 110 volt rating on a basis of a normal 800-hour life. 

Operating voltage.— In order to obtain a higher photographic 
intensity these lamps during the actual taking of the picture are 
operated at 120 volts, this being 9 per cent over voltage which gives 
a 35 per cent increase in photographic candle power. During make 
ready they are operated at 100 volts which is a 9 per cent under 
voltage. The life at the 9 per cent over volatge is estimated to be 

Tungsten Lainp Studio Lighting — Jones 


approximately 250 hours, and since the actual taking time is relatively 
short, a life of 250 hours should be fairly satisfactory. 

The reflector. — In order to utilize the greatest possible proportion 
of emitted flux it is obvious that some type of reflector must be used 
in order to concentrate the hght on the desired areas. No commercial 
reflector suitable for use with these 3, 000- watt lamps and fulfilling 
the requirements was found on the market, so it became necessary 
to design and construct one for our particular needs. Polished metallic 
reflectors of elliptical, parabolic, and spherical types were considered 
and a few preliminary trials made. No material of this type was 

Fig. 1. Diagram showing position of reflecting elements 

found which would retain high polish when subjected to the tempera- 
tures obtained with these high wattage units, nor could the desired 
distributidn of light be obtained with reflectors of these types. In 
collaboration with Mr. Capstaff, who had given this matter of the 
reflector careful attention, a reflector of the polyhedral type was 
designed and constructed which gave high efficiency and fairly 
satisfactory performance. This is of such shape that with the source 
at a distance of 12 feet from a surface an area approximately 12 feet 
in diameter is illuminated with a fair degree of uniformity. The 
reflecting surfaces are plain glass mirrors protected on the back with 
a heat-resisting coating. These were manufactm-ed for us by the 

28 Transactions of S.M.P.E., September 1925 

Bausch and Lomb Optical Company, and thus far have stood up very 
well at the temperatures reached in operation. The geometrical 
arrangement of the reflecting surfaces is illustrated in Fig. 1 which 
represents a section through the optical axis of the reflector. 

The point designates the position of the light source and the 
angle a, 52°, is the angle subtended at the light source by a line 12 
feet long passing through and perpendicular to the optical axis at a 
distance 12 feet from the source. All of the light flux emitted within 
the angle a falls directly upon the area to be illuminated. The angle 
tti represents the space required for the opening in the reflector 
through which the stem of the lamp bulb projects. Sufficient clear- 
ance around the stem of the lamp bulb is allowed for adequate 
ventilation of the unit. This angle is very nearly equal to the angle a 
and is shown in the figure. It should be understood, however, that 
this diagram is not drawn precisely to scale and is merely given for 
purposes of illustration. Having determined the space required for 
mounting of the lamp and ventilation, the angle ai is laid out accord- 
ingly, and then measuring from the boundary of this angle the angle 
h is laid off, this being approximately equal to the angle a; as a matter 
of fact it is necessary to make h somewhat larger than a in order to 
allow for the finite size of the filament assembly. The reflecting 
element ^5 is so placed that it reflects all of the flux emitted within 
the angle h back onto the area included within the angle a. The 
bisector of the angle h is incident on the reflecting element A 5 at 
point D, and is reflected along the line DS which when extended 
intersects the axis of the reflector, OL, at a distance of 12 feet from 
the source. The limiting ray OB is reflected along the line BE as 
indicated and intersects the line OM, also in the plane, at a distance 
of 12 feet from the source. The reflected image of the light source due 
to this reflecting element lies at Oi. All of the light flux emitted 
within the annular angle h is therefore reflected so as to fall within 
the prescribed limits. The second zone of reflecting elements BC and 
BiCi subtends the angle e which is equal approximately to one half a, 
and is placed as shown. The limiting ray OB is reflected along the 
line BR which intersects the line ON in the plane at a distance of 
12 feet from the light source, while the other limiting ray OC is 
reflected along the line CT and intersects the axis of the reflector OL 
at a distance of 12 feet from the source 0. Thus one half of the field 
is illuminated by the light thus reflected. The reflecting element BiCi 
placed 'symmetrically with respect to BC covers the opposite half of 

Tungsten Lamp Studio Lighting — Jones 


the field. It is obvious that a greater amount of the Hght flux could 
be thrown onto the desired area by making the element BC longer. 
This, however, results in a reflector which is excessively large, thus 
increasing the weight and inconvenience of mounting and handling. 
The figure shows only a cross section through the optical axis of the 
reflector and a plan view is shown in Fig. 2. It will be noted that this 
is octagonal in form and each zone of reflecting elements consists of 
eight plane mirrors (trapezoidal in shape) making a total of sixteen 
plane reflecting elements in the entire unit. The image of the light 
source formed by the element BC lies at the point O2. If the eye be 
placed on the optical axis looking into the reflector sixteen images of 
the filament may be seen. For points ourside of the axis a smaller 

Fig. 2. Plan view of the octagonal reflector shell 

number will be visible due to the limiting boundaries of the various 
elements. Measurements show that the illumination at a point 
lying on the 12-ft. plane, and also on the axis of the reflector, is 
approximately eight times as great as the illumination given by the 
source without the reflector. The illumination over the 12-ft. circle 
is not entirely uniform but is fairly satisfactory and when several 
such reflectors are grouped together, the inequalities of illumination 
can be sufficiently equalized for practical purposes. The first re- 
flectors of this type were built by using a shell formed of sheet metal. 
The lamp socket being held in position by a cast aluminum yoke 
fitted to the collar of the reflector, some space was allowed so as to 
provide a passage for the heated air around the stem of the lamp. 
These units were used and found to be satisfactory from the stand- 


Transactions of S.M.P.E., September 1926 

point of illumination. The reflector shells, however, were not suf- 
ficiently rigid, and it seemed advisable to adopt a more solid type of 
construction in order to minimize danger of breaking the glass 
mirrors. A pattern was therefore made and a solid shell of cast 
aluminum was thus obtained for carrying the reflecting elements. 
This is illustrated in Fig. 2 which shows the octagonal form of this 

Since these units are designed to be used largely with the re- 
flector pointing downward, the heated air tends to accumulate within 
the reflector, the ventilation by convection alone did not seem to be 
adequate and it was considered advisable in the improved models to 
provide forced ventilation. This was done by placing over the collar 

Fig. 3. 

Elevation showing assembled reflector unit vnth Ventilating blower and 
lamp socket 

of the shell carrying the reflector an aluminum cap as shown at 22 in 
Fig. 3. To one side of this cap is attached a number 00 Sirocco fan 
directly connected to a small A. C. motor. The method of attachment 
is shown in Fig 3. The stream of air from the blower enters the cap 
tangentially and directed downward so that there is a tendency to 
form a circulatory motion within the shell and the reflector. In this 
way the hot air is swept out and the lamp bulb and reflecting elements 
adequately ventilated. The mogul socket is mounted inside of the 
cap on a threaded stem which extends through the top of the cap 
and is held in position by the nuts 2 and 19. This provides a method 
of adjusting the light source in the reflector to the proper position. 
The set screw 3 serves to fasten the stem in position when the required 

Tungsten Lamp Studio Lighting — Jones 


adjustments have been made. The motor driving the fan is connected 
in parallel with the lamp and is rated at 110 volts, thus during make 
ready and rehearsal the motor runs at a relatively low speed while 
during taking, when the over voltage is impressed on the lamps, 
the motor is also subjected to an over voltage and operates at high 
speed thus giving a greater volume of air when most needed. 


Fig. 4. Plan view showing method of mounting three units on frame 

■ Pl»tn (n\ 

Fig. 5. Elevation showing assembly of triple unit 

Mounting of the reflector units. — In order to facilitate the hand- 
ling of the lamps in the studio three reflectors are mounted together 
on a single frame and are handled as a single unit. This was considered 
advisable since a fairly large number of lamps are required to il- 
luminate a set of large size and the manipulation of a large number of 


Tronsactions of S.M.P.E., September 1925 

single 3,000 watt units would be much more complicated than in 
groups of three. From the standpoint of flexibility and distribution 
it was not considered advisable_to group more than three lamps on 
one fixture. The method of assembling these reflectors on the frames 
is shown in Fig. 4, which is a plan view of the assembly, and in Fig. 5, 
which is a side elevation. The framework is formed of electrically 
welded angle iron. The central unit is mounted in a fixed position 
relative to the framework while the two end units are mounted in 

Fig. 6. Photograph showing front view of complete triple unit 

such a way that they may be tilted with respect to the framework. 
Connection is made between the central element and the outer ones 
by means of the right and left hand threaded rods, 13 and 25, attached 
to bosses on the reflector cap, and turn buckles as shown in the figure. 
By adjusting these turn buckles the inclination of the optical axes 
of the outer reflectors can be adjusted so as to converge or diverge the 
illumination as desired. The frame carrying the three units is 28 in. 
wide by 72 in. long and 11 in. deep. The sides and top are covered 
with -perforated sheet metal while the front of the framework is 

Tungsten Lamp Studio Lighting — Jones 


covered with half inch square woven wire netting mounted on a 
frame hinged to the front of the main framework. This is used in 
order to prevent pieces of glass resulting from accidental breakage 
of a reflector or bulb from falling on persons working below the units. 
The corners of the frame are truncated as shown so that the unit may 
be turned with less danger of interference with other units in its 
vicinity. This complete assembly is carried by four steel cables, 
1 / 4 in. in diameter, attached one at each corner of the frame work. 

Fig. 7. Photograph showing rear view of triple unit 

These cables go to the hoist which will be described later. Photographs 
which give a more definite idea of these triple units are shown in 
Figs. 6 and 7. The cable is attached to the framework through a 
turn buckle which is used for leveling the unit after it has been hung. 
A strain insulator is also used as protection against short circuit. 
The cable carrying the electric current enters the junction box which 
can be clearly seen in Fig. 7, and from this leads are carried to the 
individual lamps. Connections to the three motors are also made to 
this junction box in which is located a suitable fuse on the motor line. 


Transactions of S.M.P.E., September 1925 

A small pilot lamp is mounted at the side of the junction box which 

indicated at all times whether or not the motor circuits are complete. 

Method of handling the units. — Since the room in which this 

installation is made is a part of the ballet school and is at times used 













njt ' 








Fig. 8. Diagram showing dimensions of studio and position of gridiron 

as a classroom, it was necessary to adopt a method of handling the 
lighting equipment which would interfere as little as possible with 
the use of the floor space for ballet purposes. It was highly desirable, 

Tungsten Lamp Studio Lighting — Jones 35 

therefore, to adopt some overhead system of electrical distribution 
and of handling the light units, thus preventing the obstruction of 
floor space with electrical cables and lamp supports. 

Before deciding upon the method of mounting and handhng the 
lighting equipment, Mr. C. A. Livingston, Superintendent of Build- 
ings, Eastman Theatre and School of Music, and the author visited 
several of the motion picture studios in and around New York in 
order to familiarize ourselves with the equipment in use for black 
and white work. After carefully weighing the advantages and dis- 
advantages of the various systems examined a method commonly 
called the "gridiron" distribution system similar to that used in the 
studios of the Famous Players-Lasky Corporation in Long Island 
City* was adopted. This was designed to meet the requirements of 
our particular work and was installed under the supervision of Mr. 
Livingston. The author at this point wishes to acknowledge his 
indebtedness to Mr. Livingston not only for the work mentioned 
above but for his assistance in the design of all of the other structural 
features installed in the studios, and for his very efficient supervision 
of the work of installing this equipment. 

In Fig. 8 is shown diagramatically a side elevation and floor 
plan of the studio. The structural steel gridiron was installed as 
indicated at A, the distance above the studio floor being 25 ft. This 
gridiron is approximately 56 ft. long by 42 ft. wide. Six longitudinal 
slots 8 in. wide and formed by standard 8 in. channel iron extend the 
entire length of the gridiron. The hoists carrying the units shown in 
Figs. 6 and 7 are mounted on carriages which travel back and forth 
along these slots. 

The structural details of the combined hoist and carriage are 
shown in Fig. 9. The drawing at the right hand side of the figure is a 
vertical transverse cross section. AA indicate the 8 in. channel 
iron which form the sides of the slot. On top of these channel irons 
are mounted the angles BB and the vertical elements of these angles 
form the track on which the carriage operates. The slatted floor of 
the gridiron, which is formed of inverted channel iron, is indicated 
at CC. The carriage and hoist is supported on the grooved wheels 
DD. The bed plate of the carriage is indicated at E. This is a casting 
which is circular in plan and is supported by the channel irons forming 
the bed of the carriage. F is another casting, circular in plan, which 

* Jac. R Manheimer. Design of Power Plant and Electrical Distribution 
in Large Studios. Trans, of S.MP.E. Xo. 11, p. 93. 


Transactions of S.M.P.E., September 1925 

rests upon rollers carried by the bed plate E. The element F is there- 
fore free to rotate about a vertical axis. The steel tube K, perpendic- 
ular to the plane of the circular plate F and passing through its 
center, extends downward through the slot. This tube is firmly 
attached to the plate F by the central bearing as shown. Upon the 
rotating bed plate F are mounted the hoist drums H. These are shown 
more clearly in the drawing at the left hand side of the figure which 
is a side elevation. These drums are carried on bearings mounted 
directly on the plate F, and are actuated by means of worms, J, and 
worm wheels, 7, which are mounted directly upon the axes of the 

Fig. 9. Drawing showing constructional details of hoist and carriage 

drums. The worm / is driven by means of a handle attached to the 
end of the shaft on which it is mounted. It will be noted that there 
are two hoist drums each driven by its own worm and worm wheel. 
The two shafts, on which the worms are mounted, are in exact 
alignment with each other and by means of the sliding lock sleeve N 
can be rigidly connected to each other, and under these conditions 
operate as a single shaft. Thus a handle attached either to or P 
will actuate both hoist drums. If the sliding lock N is removed, 
then the two shafts and P can be operated independently. Quarter- 
inch steel cables wound upon the hoisting drum HH extend down- 
ward .through the slot and are spread out of the four corners of the 

Tungsten Lamp Studio Lighting — Jones 37 

frame on which are mounted the three reflectors (see Figs. 6 and 7). 

These cables, which are designated as RR in the figure, after passing 

through the slot are given horizontal spread by means of two sheaves, 

one mounted directly under the slot, and one at the end of the arm S. 

Four arms such as are shown by S, which together form the diagonals 

of the rectangle equal in dimensions to the frame of the triple unit, 

are carried by a heavy casting firmly mounted on the lower end of the 

tube K, and are given strength by the bracing as shown. This 

assembly, diagonal arms, sheaves, braces, etc., is termed the "spider." 

It is evident now that all elements carried upon the bed plate F are 

free to rotate with F, and in this way any desired orientation of the 

illuminating unit can be obtained. The lock G served to prevent 

relative motion between E and F, while the clamp, L engaging the 

flange of the channel iron track serves to lock the entire carriage 

into position as desired. The electrical cable supplying current to 

the unit passes down through the tube K. Each hoist drum is grooved, 

right and left hand, and serves to take up two cables. The two cables 

from one hoist drum are attached to the front edge of the triple unit 

and the two from the other drum are attached to the rear edge. By 

locking the elements and P together by means of the sleeve A^, 

the two hoist drums operate in synchronism and all four cables 

are taken up equally, thus raising and lowering the unit without 

any change in its angle of inclination. If, however, the lock sleeve N 

is removed, then the operation of will either raise or lower the 

front of the unit, thus changing its angle of inclination relative to the 

floor of the studio. All possible required adjustments of the unit are 

therefore, provided for. By moving the carriage back and forth along 

the track the unit can be shifted longitudinally with respect to the 

studio. By rotating the element F any desired orientation can be 

obtained, and by operating the hoist drums either simultaneously 

or differentially any desired height and inclination of the unit can 

be obtained. A photograph, which perhaps contains a more definite 

idea of this hoist and carriage, is shown in Fig. 10. 

This unit was constructed according to our design by the Peter 
Clark Company of New York City. Patents have been applied for to 
cover all of the novel features of the carriage and hoist, as well as the 
triple unit reflector assembly. 

Eighteen of these hoists are provided and under normal operating 
conditions three are located in each of the six gridiron slots. In order 
to provide for the necessity of concentrating a greater number of 


Transactions of S.M.P.E., Septemher 1925 

units at one side of the studio, a transfer track and carriage is 
provided at one end of the studio. This consists of a pair of rails, 
mounted about three feet above the gridiron level and extending 
across the studio, that is, perpendicular to the direction of the slots. 
From this hangs a carriage or cradle which can be moved into position 
in line with any one of the gridiron slots, and onto this the carriage 
and hoist can be rolled. The transfer carriage can then be moved 
into position in front of any other of the gridiron slots and the hoist 
in this way transferred laterally across the studio. 

Fig. 10. Photograph of the hoist and carriage in position on gridiron 

Side halconies.— Two narrow balconies are provided on each of 
the studio side walls extending practically the entire length of the 
studio. One of these is approximately 8 feet above the studio floor 
and the other about 15 feet. Guard railings are erected at the front 
edge of each of these balconies and in the guard railing posts are 
located sockets into which arc or tungsten spotting units can be set. 
These balconies provide locations from which to operate spot lights 
for sidB lighting effects. The electrical supply for the operation of the 
various sources will be discussed in a later section. 

Tungsten Lamp Studio Lighting — Jo7ies 39 

The flying bridge. — It was considered desirable to provide also 
some means of operating spot lights for use in producing back lighting 
effects. There were objections to building a permanent equipment 
for this on the end wall of the studio, and hence a movable structure 
referred to as the flying bridge was installed. Immediately beneath 
the gridiron along each side of the studio were mounted heavy 
I-beams which serve as tracks to support small movable carriages 
to which are attached one-ton chain hoists. A narrow platform 
approximately 30 in. wide and 42 ft. long was constructed of trussed 
structural steel, the ends of this platform being supported by the 
chain hoists. Sockets for setting spots are provided, and outlet 
pockets for the supply of electrical energy are mounted directly on 
the flying bridge. The two carriages operating on the side I-beams 
are linked together by a steel cable carried completely around the 
room and supported at the corners by sheaves. An endless chain 
hanging over a grooved pulley is mounted at one corner of the room, 
and serves to operate the cable. In this way one man can move the 
bridge back and forth to any desired position in the studio. The 
height of the bridge above the studio floor can be adjusted b}^ the 
chain hoists which support the ends. 

Electrical equipment. — The tungsten lamp equipment is operated 
from an alternating current supply. The feeders are three-phase, 
three-wire, 240-volt, 800-ampere, or 332-kv-a capacity. Since it is 
desired to operate the tungsten lamps at two different voltages, one 
of which is below the nominal rating of 110 volts and one above, it 
was necessary to install compensators to give the required voltage 
control. For this purpose three compensators of 50-kv-a unbalanced 
load capacity, each provided with taps for a neutral wire and for 
100 and 120 volts on each side of the neutral, are used. Three feeder 
taps are also provided so that adjustment can be made for varia- 
tions in line voltage. The switchboard is the dead front type in 
three sections, one section per phase. A double throw switch is 
provided for each triple lamp unit with an interlocking master lever 
for each five units. The double throw switches are connected to the 
100- and 120-volt leads to the compensators so that when the switch 
handle is thrown down the potential applied to the lamps is 100 volts, 
and when the switch handle is thrown upward this potential is raised 
to 120 volts. By using the interlocking master lever the voltage on 
five units can be changed from low to high simultaneously. The 
electrical energy is distributed to the gridiron in three conduits which 


Transactions of S.M.P.E., Se-ptemher 1925 

are mounted approximately 7 feet above the floor of the gridiron, 
one conduit being placed midway between each pair of gridiron slots. 
Each conduit contains five circuits, each one of which goes directly 
to one of the double throw switches on the board. Each of the triple 
units is fed by a No. 2-guage, 2- wire stage cable, terminating above 
the gridiron in a 150-ampere Anderson plug. Flush receptacles for 
these plugs are enclosed in steel boxes and point downward so as to 
be dust proof. These receptacles are mounted directh'- in line with 

4 1-1 : 1-1 *4; ; ilil-4fl 

W~#^ f--f«-«^4;^-; ;^*^-««^-^ 



Fig. 11. Photograph of switchboard 

the conduits and hence are in easy reach of a man of ordinary height. 
Three receptacles are connected to each circuit at different points 
along the length of the studio. This was necessarj^ in order to avoid 
the necessity of having extremely long cables attached to the units. 
One group of outlets is placed at about the center (longitudinally) 
of the studio and the other groups at about 25 feet to the front and 
to the rear of the central group. Of course only one unit (three 3,000- 
watt lamps) can be operated on each circuit, and care must be taken 
not to plug two units into two of the receptacles connected onto the 

Tungsten Lamp Studio Lighting — Jones 


same circuit. The electrical equipment, therefore, provides for the 
simultaneous operation of fifteen units, (45-3,000-watt lamps) from 
the gridiron circuits. In order to provide for the operaton of tungsten 
spots, side light, and footlight units, ten additional circuits of the 
same capacity are provided, four outlets being provided on each 
wall of the studio and two on the end wall. These circuits terminate 
in individual switches on the board, each group of five being operated 
by the interlocking levers. The wall pockets are so located that 

Fig. 12. Photograph showing sample set in the studio with Ughting unit in place 

connection can be conveniently made for the operation of units 
operated either on the movable floor stands or on either the lower or 
upper side balconies. 

It was considered advisable to provide also for the use of some 
arcs for spotting purposes. Eight D.C. circuits were therefore 
provided, each having the capicity of 150 amperes. Three outlet 
pockets for these circuits are mounted on each wall of the studio and 
two on the rear end wall. In Fig 11 is shown a photograph of the 
switchboard. The eight switches across the top of the board control 


Transactions of S.M.P.E., Septejnher 1925 

the eight arc circuits. The ten switches on the right hand panel 
control the A.C. wall circuits and the fifteen switches on the left hand 
panel the gridiron circuits. Switches, outlet pockets, and the lighting 
units hanging from the gridiron are all numbered in order to facilitate 
the operation of the equipment. 

The switchboard, distribution, and transformer equipment were 
designed in accordance with our requirements by Mr. Frederick A. 
Mott, electrical engineer and manager of the construction department 

Fig. 13. Photograph showing the complete studio with gridiron, triple units, 

side balconies, etc. 

of the Wheeler Green Electric Company, and was installed by that 
concern. We are indebted to Mr. Mott for the technical details 
relative to the electrical equipment. 

In Figs. 12 and 13 are shown photographs of the interior of the 
studio with the units in position. Fig. 12 shows a fairly close view 
of a set with nine of the units in position. Fig. 13 is a more general 
view of the interior showing all of the units, some of which are in 
position for illuminating a set, and the others not being placed for 

Tungsten Lamp Shidio Lighting — Jones 43 

use. In the upper part of the photograph may be seen the gridiron 
and in the extreme foreground at the top is the flying bridge, which 
in this case is not in use and is drawn as near as possible to the grid- 
iron in order to be out of the way. The side balconies may also be 
seen in this view. The 75-ampere high intensity portable arc units 
may also be seen on their floor stands. These have been used to 
some extent for spotting purposes. The results thus far are not 
entirely satisfactory but sufficient tests for n definite decision have 
not yet been made. At the present time spot lights using 10-kilo watt- 
tungsten incandescent lamps are in the process of construction. 
Preliminary results that have been made .with tungsten spot light 
using the 10 and 30-kilowatt lamps indicate that these will be more 
satisfactory than arc spots, the chief reason for the superiority being 
in the quality (color) of the illumination afforded and the size of spot 

No attempt will be made at this time to give a complete analysis 
of the illumination levels and distribution obtained with these units. 
A few values, however, may be of interest. With one of the triple 
units at a distance of 12 feet above the studio floor and pointing 
directly downward, that is with the axes of the reflectors perpendic- 
ular to the floor, an illumination of 1,500 foot candles was obtained 
directly below the central unit. The value was obtained with the 
lamps operating at the high voltage, 120 volts. The illumination 
over a rectangular area 10 x 14 feet directly below the unit was 
fairly uniform and had an average value of approximately 1,200 
candles. The illumination obtained at high voltage is 70 per cent 
greater than that at low voltage which is in satisfactory agreement 
with the theoretical value for this ratio. 

The efficiency of the system for the purpose for which it was 
designed may be illustrated by a statement of the conditions under 
which fully exposed color pictures can be made. Using the two-color 
camera, with the lenses set at approximately f/3.5 and a shutter 
opening of 180°, the fifteen units are sufficient to illuminate a 40-ft. 
set so that fully exposed negatives can be obtained at normal taking 
speed, sixteen pictures per second. For smaller sets the number of 
units required is of course proportionately less. 

Some tests have also been made to determine the efficiency of 
this system for the making of black and white pictures. Using a 
camera equipped with a lens operated at f/3.5 and shutter opening of 
180°, fully exposed negatives were obtained on a 20-ft. set with three 

44 Transactions of S.M.P.E., September 1925 

units, taking speed being normal. We consider that this compares 
favorably with the illuminating systems at present in use in commer- 
cial studios. With this number of units the heat is not at all objection- 
able, nor is the glare difficult to face. By using lamps of the same 
type in photographic blue bulbs the glare factor could be practically 
eliminated and we feel that such an equipment of tungsten lamps can 
be used advantageously for black and white work. So far as we are 
aware this is the first tungsten lamp installation of any magnitude 
which has been tried for motion picture work, and while it has been 
in operation a relatively short time the results thus far obtained lead 
us to believe this type of illumination compares favorably with others 
at present in use for black and white work; and for color work we feel 
that it is the best that can be obtained. 


Mr. Benford : Could Mr. Jones tell us the operating tempera- 
ture of the filaments during the taking period. 

Mr. Davidson: In the smaller units did you try using the 
lamps in series instead of rheostating each lamp? We have done 
this satisfactorily. 

Also did you use clear globe lamps or blue lights? 

Mr. Kelley: We have experimented with the Cooper-Hewitt, 
which we have used in combination with tungsten. Our impression 
is that where you have gold or yellow, it is better to use Cooper- 
Hewitt combined with the other light. It seems to bring out these 
colors and make them sparkle. 

President Jones: We haven't as yet measured the operating 
temperature. The lamps are so designed that when operated at 110 
volts, the efficiency is approximately the same as the ordinary 
commercial thousand-watt lamp. During actual taking, they are 
subjected to an over-voltage of 9 per cent. I do not know just what 
the operating temperature would be under such conditions. 

Mr. Burnap: It is somewhere between 3,100 and 3,200 Kelvin. 

President Jones: In using the small low voltage unit, they 
were used on the 110 volt line, three lamps being connected in 
series. We are using clear bulb lamps for color photography since 
the longer wave-lengths, which are cut off by the blue bulbs, are 
required. For black and white work, there is little doubt that the blue 
bulb lamps would be almost as efficient photographically, but for 
color work, the use of blue glass would lower the efficiency enormously. 

Discussion , 45 

Mr. Davidson: Did you use any blue to cut down the excess 
red in the tungsten? 

President Jones: No. All of the radiation of longer wave- 
lengths, red, orange, yellow, etc., are useful for color work. The 
mercury vapor lamps have been found entirely unsatisfactory for 
general color work. It is possible that under certain special conditions 
they would give fairly satisfactory results but in most cases, the 
color rendering with the mercury vapor lamp is very poor. Some 
materials such as colored fabrics may have very narrow spectral 
reflection characteristics. In case such reflection band comes at the 
point on the spectrum where there is no radiation in the light from 
the mercury vapor source the material would be rendered as very 
dark. In general the mercury vapor light is not satisfactory. 

Mr. Kelley: You have more red in the tungstens than is 
needed. Some recent pictures were made using a combination of 
arc lights, and Cooper-Hewitts and the results were excellent We 
recently fitted up a cartoon outfit for color photography consisting 
of two clear bulb tungsten lamps and two U-shape Cooper-Hewitts. 
This mixture of lamps gave all the colors on a color card in their 
correct shades. 

President Jones : I misunderstood Mr. Kelley 's first statement 
and thought he implied that the Cooper-Hewitt source was used alone. 

Mr. Kelley: Oh, no! That is impossible. 

President Jones: It is probable that a mixture of tungsten 
and mercury vapor light could be used with good results for color 
work. In building this installation, however, we wished to have the 
units of uniform type. While Mr. Kelley's point may be well taken, 
I consider it better not to have two distinct types of units to deal with. 


By Alfred B. Hitchins* 

A great deal has been written, during the past two or three years, 
on the subject of machine development, but the discussion and 
description of the various methods in use have been confined entirely 
to the machine development of positive film. There seems to be a 
strong feeling against the development of negative in any kind of 
machine and rule of thumb methods of developer manipulation are 
in force generally. There seems to be a lingering doubt about sub- 
mitting a valuable negative to machine development, yet exhaustive 
series of experimental test runs have proved that, in both theory and 
practice, properly controlled mechanical development is the most 
satisfactory method. 

When Hurter and Driffield published their splendid researches 
on the theory of photo-chemical action and established beyond 
doubt that exposure and not developer manipulation governed the 
photographic result, they proved once and for all the utter futility of 
trying to make the developer do that which can only be done by 
light. Whatever light action or exposure has done in forming the 
latent image is unalterable, whether it be too much or too little, and 
no amount of juggling the developer will ever compensate for it — we 
cannot alter the impression due to light. If the negative is under- 
exposed and we force it, nothing more than fight has impressed can 
be developed in the shadows. All that happens is that the high lights 
are clogged up or over-developed and the result is soot and whitewash. 
We have simply increased the contrast and have not created or 
conferred any detail that was not registered to begin with. 

In the case of over-exposure, if the negative is developed for a 
shorter time than usual, the result is flatness. In either case we have 
gained nothing by monkeying with the developing time, and it is 
equally true that varying the constituents or proportions of the 
constituents of the developer will not help. 

It is true that different emulsions or brands of film have different 
development velocities, or, in other words, the time of development 
necessary to gain a given degree of density and contrast varies with 
different makes. But, given a well-balanced developing formula, 

* Technical Director of Duplex Motion Picture Industries, Inc. 


Machine Development — Hitchins 




48 Transactions of SM.P.E., September 1925 

properly controlled time and temperature methods will give the best 
average results from any exposure. Control of time and temperature 
are the essence of a well designed developing machine and the less 
manual handling and examination the film has the better the results 
will be. A careful, unbiased observation of comparative tests of 
controlled development versus developer manipulation will prove 
the scientific method to be both theoretically and practically sound. 
No one understands lighting and exposure better than the high grade 
cameramen, 99 per cent of whom are fine photographers in every 
sense of the word and well know that properly controlled light con- 
ditions and exposure are the governing factors in the faithful re- 
production of the tone values of the original subject. Having taken 
advantage of all their skill in impressing a well balanced latent image 
on the film is it not logical and sensible to develop the negative under 
conditions that are controllable and constant instead of submitting a 
thing of such value to the haphazard conditions and uncertainties of 
the rack and tank method? 

There is perhaps a justifiable pride of craft in the manual develop- 
ment of negatives. The earnest worker likes to feel that he himself 
can make the negative of supreme quality, but the cold scientific 
fact remains that he cannot materialy alter what has been definitely 
effected by light. And when it comes to a consideration of cleanliness, 
uniformity, lowered cost, and increased production of better average 
quality, then there is no comparison between machine and manual 
methods, it is all in favor of the machine. 

There is nothing radical in advocating machine development of 
negatives, it is the logical and certain method of producing the largest 
output of uniformly good quality for the least expenditure of time 
and money. Twenty years ago the skilled portrait photographer 
would have laughed at the idea of taking his day's negatives and 
putting them in a developing solution at a definite temperature and 
then forgetting them for twenty minutes. He believed in dish de- 
velopment, personal examination and thought he could by developer 
manipulation make up for inaccuracy of exposure. Today the 
photographer knows better and realizes that time and temperature 
properly harnessed will produce for him the best negatives his ex- 
posures will yield. 

The germ of successful machine development is time and tem- 
perature. Time is controlled by the speed of the machine, by the 
number of tubes that the film is put through, and this not only 

Machine Development — Hitchins 49 

applies to developing but to the check bath, rinse, fixing, tinting and 
washing. Temperature is controlled by thermostatic regulators which 
maintain the developing solution at proper operating temperature. 

The machine development of positive film calls for no special 
remarks for it is rapidly becoming the accepted practice and most of 
the big laboratories are equipped with developing machines of one 
form or another. 

A long experience with machine development methods seems to 
point to some form of what is known as the "straight line" machine 
as being the most efficient and flexible type. One of the most up-to- 
date machines of this nature will be described; it embodies improve- 
ments that are the result of years of experience in developing machine 

The complete machine is shown in the illustration and the 
important parts are lettered to aid in description. The machine is 
duplex in principle, that is to say, film is processed on both sides of 
the machine at one operation. The speed of the machine ranges from 
15 to 30 feet per minute, giving, when both sides are in operation, 30 
to 60 feet production per minute. When used for negative develop- 
ment it is run at 15 feet per minute and for positive 30 feet per min- 
ute. One motor drive of one-fourth horse power operates both sides 
of the machine. 

A. The take-off reels. Two are provided on each side of the 
machine, so that a second roll can always be in readiness to splice on 
to the end of the roll in process, making the operation continuous. 

B. Compensating elevator. The film is led on to this from the 
take off reel. The elevator has a latitude of 3 minutes, that is to say, 
when it is full it will feed the machine for that time, allowing plenty 
of time for the splicing on of the second roll. 

C. The developing tubes. These are made of heavy walled 
Pyrex glass. The film is led into them from the elevator over sprocket 
and idler rolls and is held in the tubes by weighting down with Pyrex 
glass bobbins. There are twelve developing tubes and the rate of 
passage through each tube is 30 seconds when the machine is run at 
30 feet per minute and 1 minute when run at 15 feet per minute. 
According to the number of tubes that are put in use the times of 
development can be varied from 30 seconds to 6 minutes when run- 
ning 30 feet per minute and from 1 minute to 12 minutes when 
running at 15 feet per minute. Further modification of develop- 
ment times can be accomplished by the length of the loop of film 

50 Transactions of S.M.P.E., September 1925 

in each tube, the figures given above being for the maximum loop. 
The developing solution is kept in a storage tank and is pumped 
to the tubes and recirculated. During recirculation the solution 
passes through a chamber that is provided with coils, thermostatically 
controlled, and is automatically maintained at the chosen working 
temperature. To take care of evaporation and the gradual exhaustion 
of the solution, fresh developer is added continuously at a given 
point in amounts in keeping with the machine speed and other con- 

D. The check bath tube, to arrest development. 

E. The rinse bath tube. 

F. The fixing tubes, six of them, allowing the time of fixing to 
be varied from 30 seconds to 3 minutes when running at 30 feet per 
minute and from 1 minute to 6 minutes when running at 15 feet per 
minute. The fixing solution is also recirculated and the combination 
of moving film and circulating hj^po materially increases the efficiency 
of fixing ; positive film is completely fixed in 234 niinutes and negative 
in 5 minutes. The hj^po bath is kept up to full strength and hardening 
properties by suitable additions at intervals. 

G. A tile wall dividing the dark room operations from those 
that can be carried out in the light. From the fixing tubes the film 
passes thi'ough a light trap in the wall into the washing tubes. 

H. Washing tubes, twenty-fom- in all, giving washing times 
ranging from 30 seconds to 12 minutes when running at 30 feet per 
minute and from 1 minute to 24 minutes when running at 15 feet 
per minute. The wash water is circulated and changed very rapidly 
through these tubes and tests show that all hypo is removed in 10 

I. Tinting tubes, five of them, and an additional rinse tube. 

J. Air jets, blowing on the film on both sides and removing all 
surface moisture and drops. After passing through these air jets the 
film contains only retained moisture and so all drying and tear marks 
are avoided. 

K. A compensating elevator, with a time latitude of 5 minutes. 
Under normal running conditions the elevator is kept about three- 
fourths full. The time latitude is sufficient to allow of starting and 
stopping, changing speeds and for taking care of any break that 
might occur in the drying cabinets. 

L. The drying cabinets, divided into three compartments each 
side, each loop of film is on an individual compensating elevator 

Machine Development — Hitchins 51 

which is connected through an electrical circuit to an alarm system so 
that in case of over filling, breaks, or other conditions a lamp on the 
compartment housing lights up as a warning and the necessarj^ 
splicing or changes in speed transmission can be attended to. The 
time of passage through the drjxrs is on an average 28 minutes. All 
air is conditioned and cumulated. The fact that the film is continually 
moving in a sinuous manner during drying is an advantage, film so 
dried will remain more flexible throughout its life and will behave 
better in the projector than film which is stationary dm^ing drjdng. 

M. The take up reels, for receiving the film as it leaves the 

X. The air intake, connected with the ah conditioning system, 
the air having fii'st been washed, then heated to tempertaure and 
properly humidified. The drying ah is very important and there is 
no doubt that drying conditions have a marked effect on the life of 
the finished film. It is poor practice to completely dry out film and 
chance it coming back to something like proper moisture conditions. 
Film should be dried under known conditions of temperatm^e and 
humidity as determined by its life, its continued flexibilit}' and lack 
of brittleness. 

Each of these machines are provided with suitable decking and 
railing so that all parts are readily accessible. All tubes are fitted 
with pet cocks for draining and cleaning. The use of PjTex glass 
tubes throughout is a great advantage over the old lead or wood 
tanks. They are easier to keep clean and as the interiors are \dsible 
there is no excuse for letting them get dhty. Also the glass tubes do 
not break up under the action of the various solutions or become 
soaked up and incrusted with chemicals as happens in the case of 
lead or wood tanks. 

The advantages of machine development are mam^ There is 
practicall}" no manual handling, and fewer finger marks, scratches 
and tears. There are no spots of unequal density such as occm' at 
the tops and bottoms of racks; no silver stains or ah' bells, and, last 
but not least, there is the saving of labor. With this machine fom* 
men can tm^n out the work that would requhe twentj'-five men using 
the older methods, and the product will be cleaner, better, and more 

Taking into consideration the average range of exposures and 
subjects that come in from the cameramen, machine development 
of negatives gives a better net result than can be obtained by any 
method of so-called development control. 

52 Transactions of S.M.P.E., September 1925 

In view of the different behavior of the various makes of j&lm, 
so far as their development speed, time taken to arrive at a chosen 
contrast, and density, test strips are made under correct time and 
temperature conditions and, this having been found, the machine is 
set at the proper speed to accomphsh the desired results automatically. 

The negative emulsions of the present day are wonderful pro- 
ducts; they have sufficient latitude in exposure and are suitable in 
every way to yield the best average quality with machine develop- 


Dr. Gage: I should like to ask the speaker if this machine 
differs from machines for developing positives. 

Dr. Hitchins: The only difference is speed. When developing 
positive it is run at 30 feet per minute and when developing negative, 
requiring longer times, it is run 15 feet a minute. 

Mr. Richardson: I should like to ask what granulation is due 
to? Is it due to the developing process? You can notice it in the 
front seats and I think the attention of the Society should be directed 
to the elimination of this evil. 

Dr. Hitchins: Mr. Jones in his paper a few meetings ago 
described all the things that tend to produce these effects. One 
influence is exposure and the effect is further increased by injudicious 

Mr. Crabtree: Do you have much trouble with breakage of 
the tubes? I should like to have information as to the exact method 
of circulation in the tubes to maintain the composition of the de- 
veloper constant and whether you have any data with regard to the 
volume of renewal developer required per foot of film. Also have you 
information on the suitability of various materials for constructing 

With regard to the development of negative film on the machine, 
it is interesting to know that negatives are being actually developed 
commercially, and I agree that in the case of the average negative 
exposed in the studio, the latitude of the film and the uniformity of 
exposure is such that good results can be obtained. In the case of 
negatives exposed on short scenes of widely varying brightness 
contrast, I don't think it is practical to use a machine. The object 
in negative development is to get all the scenes so that they are of 
uniform density contrast, or of such density contrast that when the 

Discussion 53 

positive prints are all developed for the same time, the desired screen 
contrast is secured. 

In ordinary photographic work, the professional photographer 
can compensate for lack of correct contrast of his negatives by using 
printing papers of varying contrast. In motion picture work, since 
positive film is available in only one degree of contrast, in order to 
vary the contrast of the print from any particular negative, it is 
necessary to vary the time of development of the positive which is 
very undesirable. 

Let me repeat that it is desirable to so develop the negative that 
correct positive prints from all the scenes are obtainable by a constant 
time of development of the positive film. In case the negative con- 
sists of a number of scenes exposed on subjects of widely varying 
brightness contrast, the only way to secure this end is to develop 
each scene separately. If the negative consists of onl}^ one scene, or 
of scenes of subjects having the same brightness contrast, then 
machine development is satisfactory. 

Of course, on most machines it is possible to vary the time of 
development from scene to scene providing the scenes are not too 
short, but with a scene of say 2 or 3 feet in length, it is almost im- 
possible to give this, say, 9 minutes development when the scenes on 
each side of it require, say, 4 minutes. 

Dr. Hitchins: We have found that even with short scenes the 
latitude is .sufficient to make machine development possible. It is 
being done every day. The metal used around the machine and on the 
sprockets is monel. The various details are given in the written 
paper, and I do not need to go into it now. Breakage of the tubes is 
very rare. The machine feeds easily and smoothly, and I do not 
think there are more than one or two breaks on an eight hour shift. 

Mr. Briefer: I am inclined to agree with Mr. Crabtree as to the 
necessity of handling separately the many small scenes taken under 
different lighting conditions and of different pictoral composition. 
The ultimate requisite is to provide negatives capable of producing 
a band of positive prints of quite even density throughout. If, as 
Dr. Hitchins says, machine development will accomplish this result, 
the method is desirable. My own opinion is in doubt. 

Dr. Hitchins: I am sorry to have to disagree with good friends, 
but I know that on a production basis, the plan is workable. Timing 
is simple and the printer has nothing to worry about. Varying den- 
sities are taken care of by automatic light changes on the printer. 


By T. K. Peters 

It may seem presumptious for me to write this plea for a museum, 
when there are others in the Society who are far better fitted to take 
up the task, as for instance, Mr. Jenkins, who has made a beginning 
in this dkection b}^ placing in the Smithsonian Institution some of 
his first apparatus. But as no one else has stepped forward to do so, 
I have been endeavoring to gather material for the project. I feel 
as though I were stealing ]\Ir. Jenkins' thunder, but in a measm^e he 
has brought this condition about, for it was due to my perusal of his 
book. Animated Pictures which I purchased in 1897, that I became 
fired with the ambition to also make Chronophotographic pictures, 
or in other and more modern language become a "movie" man. 

Seriously though, I want to present to the Society a subject 
that should be of vital interest to everyone engaged in the industry; 
the formation of an historical section of the Society and the establish- 
ment of a museum of historical material giving the observer a chance 
to visualize the early stages of the art. Every time I see an old bit of 
machinerj^ or an old negative, my mind travels back through a long 
list of incident and scenes connected with the earlj^ history of 
anunated pictm^es. Therefore, I must ask your pardon if I digress a 
moment from the subject of the museum proper, in order that you, 
too, ma}^ see a few of those scenes and realize just what a museum of 
the kind would mean to us, who kre still in the industry today and 
who saw its yesterdays. For, like many of j^ou who will be present 
at this meeting, I have lived motion picture history while others have 
written of it. 

In vny boyhood da3^s here in California I had a photographer 
friend who knew ^Vluy bridge in San Francisco, and he often regaled 
me with stories of the eccentric old Englishman. Then, as I grew 
older after passing my early j^outh in Mexico, I became conscious 
that my great work in life was to be a rival to Hermann or Keller. 
Being of the mechanical turn of mind, I decided to begin making my 
apparatus, and with that end in view I purchased a book called 
Magic and Stage Illusions and started out to become a magician. 
Unfortunately^ while able to make the apparatus, I failed deplorabty 


Museum of Motion Picture History — Peters 55 

in presenting it, so was forced into the minor role of assistant on the 
stage, but leading man in the work shop; in other words, I had the 
pleasure of seeing someone else present the illusions which I built. 

In this capacity I joined forces with two Hindu magicians and 
toured the Eastern States and from there we went to England and 
on to the Continent. We separated in Paris owing to a lack of agree- 
ment on the part of the partner regarding the affections of a young 
French girl. Left to my own devices, I wandered around Paris until 
one day I stumbled upon a friend I had known in California, a French- 
man, who had returned home and was then engaged with a concern 
making animated views. 

I understood at once what he meant, for my book on magic 
and stage illusions contained an account of the new wonder, and, 
pursuing my studies further, I had purchased a book written by 
Francis Jenkins of Washington which contained a complete descrip- 
tion and being interested in amature photography I felt that I was 
competent to follow the new profession. With this idea I went to the 
studio where my friend was engaged and had an interview with the 
manager, to whom I unfolded my desire. He was cordial and sym- 
pathetic but was unable to help me at the moment, but suggested, 
when I told him that I had had experience as a photographer, that I 
try and get a camera and make some film which he would buy if it 
was good. I went to the largest dealer in photographic goods, a man 
named Thibault, and purchased a camera which had just been con- 
structed by a young man named Charpentier, which the Lumieres 
had taken up and were using. Armed with this I went on my own, 
getting views which I sold to the Pathes and to Daddy Paul of London. 
Both of these firms were making kinetoscopes in imitation of the 
Edison product which had become the rage all over Europe. As yet 
we had no projected pictures in common use, and our negatives were 
made for the kinetoscope and in fifty foot lengths. My particular 
product was scenic views entirely, such thrilling views being recorded 
as "Boat Traveling up the Seine," "Train Leaving the Station," 
"Breaking Waves," "Rough Sea in the English Channel," etc. 

My camera when first purchased had sprockets made to the 
Lumiere standard, that is, they had but four teeth as the film used 
Lumieres had but one perforation per picture. I had this changed 
to the Edison standard which was fast becoming fixed as the universal 
perforation for film, due to the fact that Edison sold more kineto- 
scopes than his competitors and the}^ were more busy suppljdng film 
for his machines than their own. 

56 Transactions of S.M.P.E., Septeniher 1925 

I retui'ned to California in 1900, which I regretted as soon as I 
arrived, for I found that there was no business there in the making 
of animated views, so I laid mj^ camera aside and went back to stage 
illusions, scenery and magic apparatus. I kept in touch with activi- 
ties in the East however, through a friend, and occasionally received 
such thrilling news as the fact that nickleodeons were being opened 
up daily and the craze was spreading like wild fu'e. The Eden Musee 
and several other houses were running pictures regularly, and they 
had gotten out a small outfit that could be put in a trunk, and gave a 
dazzling light with oxygen and lime pastilles. I nearly fell for the 
purchase of one of these outfits, in fact I wrote to Lubin and re- 
ceived a catalogue describing his NEW TWENTIETH CENTURY 
terms that I was on the point of ordering one when I received a 
letter from my friend (Daddy Paley) telling me of a new stunt that 
was going to be aU the rage. The idea was to erect an imitation 
raihoad coach in a penny arcade to which an admission fee was to be 
charged, your ticket to be taken by a uniformed conductor as you 
entered the car. When the car was full the conductor would shout 
"All Aboard/' you would hear the hiss of air brakes, the wheels 
would begin to revolve, the coach swayed this way and that, and 
then before your ej^es opened up a vista of track and you were off 
down it traveling through strange lands, over hill and dale, through 
tunnels, over bridges and thi^ough streets of foreign cities. I fell for 
this idea and taking my camera I started out to do a little travehng 
myself, so that others might travel ^dcariously via the medium of 
my pictures. 

I embarked for the Orient and for the next two years I sweated 
in the tropics, dried out in the Deccan, and hit most of the high 
spots from Tokio to Ceylon. I arrived home in San Francisco in 
time for the big event of April, 1906, and saw my entire two years 
work, my camera, and ever3^i:hing I had go up in smoke in fifteen 
minutes. For the next three years I operated in theatres or ran my 
own in Los Angeles and San Francisco, and unsuccessfully endeavored 
to get some company to come out to California to make pictm-es. At 
last Colonel Selig came out to stay, although the Biograph Company 
had come out for a few months the previous year. Then the Bison 
studio was opened, the second one in Los Angeles, and the race was 

Museum of Motion Picture History — Peters 57 

A month or so after the Bison Company arrived I joined them 
and from that time on I have been continuously employed in the 
industry in one capacity or another. In 1909 we were making one 
thousand foot pictures, turning out an average of two such pictures a 
week. We had a thoroughly modern studio on the site where the 
Max Sennett studio now stands in Edendale. The office and the 
laboratory were across the street. The studio proper consisted of a 
three room unplastered bungalow, two of the rooms being reserved 
for ladies and one for the gentlemen for dressing rooms. Behind the 
house the stage stretched away into the distance for twenty-five feet. 
Our lighting system was rated at 190,000 candle power, being the 
sun, the stage was screened and the light diffused by means of a 
canopy of bleached muslin, and on cloudy days our life was made a 
torment by shouts to "Put up the canopy — take down the canopy," 
whereat all hands would join in and grab the sheet. 

Our settings were gorgeous, for we possessed two enthe interiors 
consisting in all of about twenty canvas flats, including center door 
fancy and doors and windows. It kept us busy repainting those sets 
in preparation for the next week's work. As film was an important 
item, and as no well regulated story that had been brought up proper- 
ly could have more than one thousand feet, our director, Charlie 
French, would take out his stop-watch and time carefuUy each 
rehearsal. If a scene ran over in action the fifteen or twenty seconds 
allotted to it, the script would have to be re-written right on the 
spot. This was no great matter, however, as it seldom ever exceeded 
one typewritten page, something like the following: 

Scene 1. Jim discovered. (5 feet) 

Scene 2. Comes down to camera. (5 feet) 

Scene 3. Canyon stream, Marjorie discovered. (6 feet) 

etc., etc., etc. 
We were, of course, perforce, Hmited to two interiors in one reel 
and so the story had to center around those two or bust. 

Up to about 1902 the longest pictures were not over 500 feet, 
and they rarely reached this figure. About 1902, however, a picture 
appeared called The Astronomer's Dream in the unprecedented length 
of 1200 feet, but long after that date the popular picture was from 
fifty to one hundred and fifty feet. 

In looking over some old film catalogues of that date I find such 
interesting subjects as: 

58 Tra?isactwns of S.M.P.E., September 1925 

Hurry up. 50 feet 

"Here is one to fool you," the catalogue says. "As the char- 
acters disappear in the air, you sit and wonder how it hap- 
pened. By no visible aid they jump over a fifteen-foot wall 
and appear to go through the same maneuvers, much to 
your surprise and amusement." 
Another super-featm-e of that date was this one. Will somebody 
please page Mr. Ford Sterling, or Max Sennett. 
''The Inexhaustible Cab. 90 feet. 

This is a remarkable picture! A hack drives up to the curb 
on a prominent street and a clown jumps out. He proceeds 
to fill the hack by notifying the passers-by to get in. Thu'ty- 
two persons enter the carriage built to hold but four, but 
none are seen to get out." 

About 1905, as my records show, we had such thrillers as The 
Nihilists in seven magnificent sensational scenes! In length 841 
feet it was produced by the Mutoscope and Biograph Company, 
which had abandoned its early standard of 2-% inches in width and 
was following the popular fashion using Edison standard. We also 
had an anticipation of the Volstead reaction in a film called The 
Moonshiners, 960 feet long. Then, too, appeared the first Westerns, 
Kit Carsons, 775 feet long, and Indians and Coivboys in six scenes, 
590 feet long. Gloria Swanson's prototype harrowed us with the 
struggles of the poor working girl in a picture called Annie's Love 
Story in seven pitiful scenes as follows : 
Scene 1. Betrayed! 
Scene 2. From Work to Pleasure 
Scene 3. Abandoned! 
Scene 4. Dying of Hunger! 
Scene 5. Letter to the Parents 
Scene 6. Terrible Expiation 
Scene 7. In the Hospital 
Annie croaked in the last scene and there was not a dry eye in the 

Our thrillers were represented by the Life of an American Fire- 
man, 425 feet, seven scenes of daring gamble with death from smoke 
and flames; then the Great Train Robbery in fourteen scenes, 740 
feet long. No thriller made since has caused the cold chills to run 
down my spine as did the last scene in that memorable drama. It 
was the first close-up! A life size view of Barnes, the outlaw chief — 

MuseuHi of Motion Picture History— Peters 59 

his face stamped with determination and showing his heartless natm-e 
— appeared on the screen. Suddenly he hfted a pistol and, pointing 
it at the audience, fired point blank! The excitement was intense; 
strong men paled and frail women fainted. Everyone in the audience 
ducked his head and was glad when it was over, but my, what a 
thriller it was! Then came the chase picture, an EngUsh production 
called the Daylight Burglary. Costume pictures such as Marie 
Antoinette; magic pictures which anticipated all om- double exposure 
of a later day; microscopic pictm-es such as The Drop of Water, made 
in 1899, the negative of which is still in my possession, and many 

So you see. I have truly lived motion pictm-es, and being a 
collector, (my wife says that one of my ancestors must have been a 
junk man) I have gradually accumulated a lot of material bearing 
on the early history- of cinematography, and I suppose others have 
done the same. What I propose now is that we pool these exhibits 
and add to them while we are able to get the material and thus form 
the first ^Motion Pictm'e ^Museum. During the last few years I have 
spent a great deal of time finding out where old machines and film 
were available and collecting data regarding early cameras and pro- 
jectors prior to 1896. In 1920, assisted by two other persons, I spent 
nearly six months in going through, page by page, everj^ specification 
for letters patent since 1860, picking out everj^ patent that related 
to motion pictures and making a list of them for reference. These 
will prove invaluable in reconstructing old models. I hope to see a 
museum established and have tentati^'ely envisioned the following 
Section A. History and Historical Models 

This would contain originals or models of the following machines: 

Plateau's Zoetrope, Thaumatropes of various patterns. 

Brown's Lantern of 1860 with Geneva movement and "Pross" 
<hutter (This type of shutter is in use at the present day.) 

Hejd's Phasmatrope, ]\Iuybridge's cameras and Zoopraxinoscope 

Donisthorpe's Kinesigraph, Demeny's Photoscope 

^larey's Camera and Projector, Le Prince's sixteen Lens Camera 

Levison's Patent, Ancheutz's Tachyscope 

Jenkins' Phantoscope, Edison's Kinetoscope 

Lubin's Cineograph, Selig's Polyscope 

Edison's Exhibition and Universal ^Models 

Spoor's Kinodrome, Powers' ]\Iodel Xo. 1 

60 Transactions of S.M.P.E., Se-ptember 1925 

LeRoy's Acmegi-aph, the Viascope, the Optigraph 

Schneider's Mirror Vitae 

The Motiograph and Edengraph, etc., etc. 

Modern machines of both American and foreign make 

Models of all types of intermittent motions mounted on boards 
and so arranged that they may be operated by hand for stud}^ 

Cameras from Muy bridges down to date 

Illmninants, such as oil lamps, gas lamps, lime lights, alcohol 
lamps, oxjdith outfit, early arc lamps, modern arcs and modern 

Laboratorjr'machinerj^, past and present 

Developing outfits, printing machines, and perforators 
Section B. History of Film 

Early attempts at making film 

Paper negatives 

Glass plate motion pictures 

Gelatine negatives 

Early Eastman, Carbutt and Luniiere film 

Film manufacturing machinery 

Earljr film standards, Edison, Biograph 

Demeny and Lumiere standards 
Section C. Historic film-making epochs 

The first motion pictures on glass plates 

The first pictures with paper negatives 

The first celluloid fi'm pictures 

Early fifty footers 

The first 500-foot picture 

The first 1000-foot picture 

The first two-reel picture 

The first three-reel picture 

The first five-reel picture 

The first chase picture 

The first comedy 

The first melodrama 

The first western 

The first trick picture 

The first microscopic picture 

The first scenic 

The first close-up 

The first fade-out and fade-in 

Museum of Motion Picture History — Peters 61 

Great films marking important steps in tke art, such as Civiliza- 
tion, Dante's Inferno (Cines), Birth of a Nation, The Golden Wedding, 
etc., etc. 

Films depicting historical events since the advent of the motion 
picture as a recorder of history. 

Educational film and records of great exploring expeditions 
Section D. [Bibliography and Patents j| 

Catalogues of early day apparatus 

Early posters 

Photographs of old time companies 

Stills from old pictures 

Clippings relating to the industry 

Trade papers, the Film Index, the Slide Review, the Motion 
Picture World, the Motion Picture News, the Kinematograph and 
Lantern Weekly, the Property Gazette, the Cine Journal and all foreign 

Books and papers containing references to motion pictures 

Statistical data in regard to the industry 

Patent specifications, United States, England, France, Italy, 
and Germany 

Files and Transactions of the Society 

Technical papers and reports 

Yearbooks and directories 

Research material, such as books on costume, 

Furniture, manners, and customs, antiques, etc., etc. 
Section E. Studio Construction 

Models in minature of every studio marking a step in advance 

of the art. 

Photos and data regarding studio construction and equipment 
Section F. Motion Pictures other than Standard 

Models and examples of plate motion pictures, continuous, 

motion picture apparatus, miniature movies such as Erne- 

mann's, the Cinescope, etc., paper pictures, the spirograph, 

disc machines, Pathescope, Cine-Kodak and other narrow width 

gauge films and apparatus, Widescope and other wider than 

standard devices, Picturol and other film stereopticons, film 

targets, paper book films, mutoscopes, talking picture devices, 
etc., etc. 

Many other exhibits will suggest themselves to j^ou, but in the 
main, this is a brief outhne of what might be accomplished to preserve 

62 Transactions of S.M.P.E., September 1925 

to posterity many things now daily being lost to history. I present 
the idea to the Society for its earnest consideration as a body or as 
individuals, with the hope that in the near future it may be a realiza- 


Dr. Mees: There is a numerical statement in the paper which I 
think should be corrected before it is published. He says the sun has 
an intensity of 196,000 candle power. I have just made a rough 
calculation and figure that it is about a hundred billion quintillion. 

With regard to this paper, I think it is useful to have a list of 
what should be in a museum. Film manufacturing machinery would 
take up a good deal of room; in fact, it would not seem altogether 
possible, and I am afraid that we will come back to the stumbling 
block of all human desires — expense. 

Mr. Richardson: I think these things should be gathered as 
soon as can be, and I think it is the duty of the Society to collect 
them. I think if the matter were broached a good fund could be 
collected, a committee appointed, and these things put in a museum. 
I have things which I should be glad to turn in. 

Mr. Porter: Some time ago, the Society had a Historical 
Committee, and they made a start in a manner in which I think this 
thing might be handled. They collected things relating to the past 
history of the art, and turned them over to the Smithsonian Insti- 
tution. Probably they could not accept such a large collection as 
Mr. Peters suggests, but I think a Historical Committee under the 
guidance of the Society could collect such things and vouch for their 
authenticity and that the Institution would accept the material, and 
I don't know where it could be better preserved than in Washington. 

President Jones: It seems to me that some action or recom- 
mendation should be made at this time. I should like to entertain 
a motion. 

Mr. Porter: I suggest that the Society appoint a Historical 
Committee of the Society of Motion Picture Engineers. 

Motion carried to appoint a Historical Committee of the Society. 


By F. H. Richardson* 

When one seeks to delve into the history of the motion picture 
industry during the period we usually refer to as "formative" — the 
space of time during which the inventions upon which the future 
success of the industry would be based were in process of discovery — 
one is immediately confronted with many apparently conflicting 

When the writer undertook the preparation of this paper, he had 
nothing more in mind than the showing to you, by means of pro- 
jected stereopticon slides, certain old pictures in his possession, 
together with some samples of old films and the relation of certain 
historic facts then in his possession. 

When the time came for serious consideration of the matter, 
however, certain things came to the fore in mental vision which very 
greatly altered the plans. One by one the pioneers of the early days 
are slipping out into ghostland, and few indeed have left any con- 
sistent written record of their achievements in the industry. William 
T. Rock, Sigmund Lubin, Nicholas Power, Edward Earl, Frank 
Cannock, and others have passed into the Eternal Shades, and in 
every case, so far as I know, we must now depend upon bits of 
information picked up here and there for the very incomplete record 
we have of their doings in those early days around which so much 
interest centers. 

We still have with us, however, some men who were pioneers 
on the very frontier of the industry, and it seemed to me to be of real 
importance to secure from them a personal, written statement of their 
activities in those days, for while we hope and trust they may be with 
us for many years, still, who may say when the Grim Reaper will 
speak the word which all humanity must obey at the last? 

With this thought in mind I have approached Thomas A. Edison, 
George Eastman, Thomas Armat and C. Francis Jenkins, each of 
whom has been kind enough to drift back in memory into the past 
and set forth for the records of this Society their own personal 
recollections, supported in many instances by records, official or 
otherwise, as to their own individual activities during the period when 
the motion picture industry was in the process of changing from a 
peep-hole affair into the life size motion picture which we know today. 

* Motion Picture World, New York City. 


64 Transactions of S.M.P.E., September 1925 

I have also been able to induce Mr. Albert E. Smith, President 
of the Vitagraph Company of America, to set down for us a record of 
his own activities in the early days, Mr. Smith and Mr. J. Stuart 
Blackton having been the original incorporators of the Vitagraph, 
which was, so far as I know, (though I do not make it as a statement 
of known fact), the first producing corporation outside of the Edison 
Company, and certainly the only producing company of them all, 
including the Edison Company, which started in the very early days, 
has endured through the years and is today still producing motion 
pictures. Also, it was the Vitagraph Company which created the 
very first "Star," who was Miss Florence Turner, long known as 
the "Vitagraph Girl." 

The statements of all these various gentlemen are in the form of 
letters prepared and signed by them personally; hence, there can 
be no question as to their genuineness, or that they contain anything 
not personally written and approved by them. For reasons you can 
readily understand, I desire to retain the originals of these letters in 
my possession, when the records of the Society have been completed 
so far as they are concerned. I would therefore suggest, if I may, that 
these letters be incorporated into our proceedings in the form of cuts 
made from the originals. 

I also take the liberty of most respectfully suggesting to this 
honorable body that a committee be appointed by its President to 
examine into and, so far as possible, reconcile any conflicting claims 
as between the various early inventors, most of which are, I believe, 
more apparent than real. 

First, I will present the statement of Mr. Thomas A. Edison, who 

Cable Address "Edison, New York" 

From the Laboratory 

Thomas A. Edison 

Orange, N. J, 
January 24, 1925 
Mr. F. H. Richardson, 
516 Fifth Avenue, 
New York, N. Y. 

Dear Mr. Richardson: 

In accordance with your request I will give j^ou a brief account of my work 
in the development of the motion picture, with the hope that it will be filed in the 
proceedings of the Society, so as to constitute a permanent record. 

What Happened in the Begi^inifig — Richardson 65 

One of m}'' early notes on the subject made shortly after the kinetoscope 
was invented, not later than 1890, was the following: 

"In the year 1887 the idea occurred to me that it was possible to 
devise an instrument which should do for the eye what the phonograph 
does for the ear, and that by a combination of the two all motion and sound 
could be recorded and reproduced simultaneously. This idea, the germ 
of which came from a little toy called the zoetrope and the work of Muy- 
bridge, Marey, and others, has now been accomplished so that every change 
of facial expression can be recorded and reproduced life size. The kineto 
scope is only a small model illustrating the present stage of the progress, 
but with each succeeding month new possibilities are brought into view. 

"I beheve that in coming years, by my own work and that of Mu}'- 
bridge, Marey and others who will doubtless enter the field, grand opera 
can be given at the Metropohtan Opera House at New York without any 
change from the original and with artists and musicians long since dead." 

I knew, of course, that both Muybridge and Marey had been able by 
photography to produce the illusion of motion by first securing instantaneous 
photographs of a single cycle of movernent and indefinitely repeating the sam.e 
and that they had actually employed projectors by which the moving image 
would be shown on a screen. The work of these two pioneers was essentially 
scientific and in no sense utilitarian; they were interested only in analyzing 
movement and not in creating a source of entertainment. Their pictures were 
taken on plates and therefore were hmited in number, so that a continued ex- 
hibition necessitated the constant repetition of a single cycle of movement. 
Furthermore, with both Muybridge and Marey, the photographic images were 
located centrally on the plates and for this reason when projected on the screen 
the image of the subject remained stationary with its arms or legs in motion. 
It was because of this limitation that, with the early pictures of Muybridge and 
Marey, it was not possible to utilize a distinctive background and therefore the 
pictures were taken before a screen of uniform color. 

When I first turned my mind to the subject in 1887, it was with the thought 
of creating a new art. I was not interested in analyzing motion because that had 
been done with brilliant success by Muybridge and Marey before me. Just as 
with the phonograph which makes a permanent record of an indefinite number 
of successive sounds, I wanted to make a permanent record of an indefinite 
number of successive phases of movement, doing for the eye what the phonograph 
had done for the ear. This meant the photographing instantaneously of a scene 
as viewed hy the eye and involved the following problems: 

1. The pictures had to be taken from a single point of view and not from 
a changing point of view as with Muybridge and Marey. In other words, the 
camera should not move with respect to the background but the moving object 
or objects should move with respect to the camera — exactly the reverse of What 
had been done before. And taking the pictures from a single point of view meant 
the use of a single lens. 

2. The pictures had to be taken at a sufficiently rapid rate to give a smooth 
and uniform reproduction without jerking; that is to say, the displacement be- 
tween the succeeding photographs had to be made very small. With my early 
pictures the rate at w^hich they were taken varied from 40 to 50 per second. This 
gave a smooth and beautiful reproduction even though the movements photo- 
graphed were quite rapid. With the modern art this rate has been reduced to 

66 Transactions of S.M.P.E., September 1925 

about 16 per second, solely in order to prolong the exhibition. Therefore sudden 
and rapid movements are avoided. 

3. The reproduction of the photographs either by direct view or by pro- 
jection on a screen, had to be so effected that the interval between successive 
images would be less than one-seventh of a second. This was a purely physiological 
limitation made necessary to take advantage of the phenomenon of persistence 
of vision as had been done for many years with the zoetrope and toys of that 

4. Since my conception involved the thought of permanently recording 
and reproducing a scene of indefinite duration, the use of disks or wheels on which 
to carry the pictures, as had been proposed by Muybridge and Marey, was 
impossible. A carrier of indefinite length was required and my conception in- 
cluded taking the photographs on and reproducing the positive prints from a 
ta'pe of light, tough, flexible material, such as a narrow celluloid film. In this 
particular development I was very materially assisted by the intelligent and 
hearty cooperation of Mr. George Eastman of Rochester, New York. At the 
time the invention was being developed by me, it was the accepted belief that 
the size of the grains of a photographic emulsion bore a definite relation to its 
sensitiveness and that a very high speed film must necessarily be one with very 
large grains. If this belief had been true it would have b?en difficult to secure 
satisfactory results, especially if the photographs were enlarged on the screen. 
However, I did not beheve it was true, and thanks to the skill of Mr. Eastman 
and his assistants, I was able to obtain from them for my experimental work and 
later for commercial use, an extremely sensitive film of very fine grain. 

With the problems above stated before me, I took up my experimental 
work late in 1887 or early in 1888. As a preliminary and to test out the feasibility 
of my ideas, the first photographs were made on a cylinder (somewhat resembhng 
a phonograph record) turning continuously, the pictures being of small or almost 
microscopic size and being arranged in a continuous spiral line on the cylinder. 
A positive print of the photographs was then made and placed upon the cylinder 
which, upon being again rotated, gave a reproduction of the original scene by 
illuminating each picture as it passed the eye by means of an electric «park. This 
was a purely tentative experiment and was eminently successful, a perfect re- 
production of the object in motion background and all being secured. 

I immediately perceived that my original conception of 1887 was entirely 
feasible and that it was possible to make a permanent record of a continuous 
scene just as it had been possible to make a permanent record of a continuous 
musical selection. 

But the first experimental apparatus was obviously impracticable not only 
because the pictures were too small but also because the duration was limited 
by the length of the spiral path. The pictures were small because with the first 
experimental apparatus the sensitive surface moved continuously; to have made 
them larger would have meant inevitable blurring. I concluded, therefore, that 
in order to make larger pictures so as to secure sharp impressions it would be 
necessary to move the sensitive surface intermittently many times per second, 
thereby permitting the exposure to be made when the surface was stationary. 

Turning then to my original thought of using a continuous film, I first 
employed a film of a width of one half inch but found that the pictures were still 

What Happened in the Beginning — Richardson 67 

too small for satisfactory reproduction especially if enlarged by projection on a 
screen. I then experimented with photographs one inch wide by three-quarters of 
an inch high. These dimensions were adopted by me in 1889 and remain today 
the standard of the art. 

The problem then arose as to the mechanical possibilities of feeding such a 
film intermittently past the field of a camera lens many times per second with the 
assurance that the film would be stationary at the instant of exposure and not 
shaking and vibrating to blur the image, and with the further assurance of such 
accuracy that the succeeding photographs would be exactly superposed one upon 
the other in reproduction. Various methods and schemes were experimented with 
for thus feeding the film and I concluded to adopt the scheme of using sprocket 
holes or perforations outside the photographs in order to permit the film to be 
engaged accurately by the feeding devices and to be jnoved always precisely the 
same distance in making the successive photographs. In forming the sprocket 
holes in the film I first used only a single line at one side but finding this unsatis- 
factory, I utilized two lines of sprocket holes spaced so as to provide four holes 
for each picture which also has been and now is the present standard of the art. 

Very many forms of start and stop mechanism were tried and by the summer 
of 1889 a satisfactory arrangement was adopted by me and was embodied in an 
actual full size camera by means of which the first motion pictures were taken on 
a celluloid film. These pictures were made in the summer of 1889; they were 
exactly like the present pictures except that they were taken at a considerably 
higher speed. In the latter respect they were actually superior to the present 
practice of the art, because the reproduction was smoother and less jerky. 

Having by a long course of experiments thus made my first successful cam- 
era in the summer of 1889, I apphed for a patent on it on August 24, 1891, and 
the patent thereon issued August 31, 1897, No. 589,168. This patent with its 
several reissues was recognized by the early manufacturers as the fundamental 
patent in the art and royalties under it were paid to me by the American manu- 
facturers of films until its expiration in 1914. 

My first camera constructed by me in 1889 and covered by this patent 
disclosed the following features which have always been utilized in the art: 

1. A single lens. 

2. A long celluloid film carrying a sensitive surface and having two rows 
of sprocket holes. 

3. A reel from which the film is unwound and a second reel on which the 
film is wound after exposure. 

4. Mechanism having a minimum inertia for moving the section of the 
film between the two reels intermittently past the lens many times per second, 
the film being stopped and brought to rest at each exposure. 

5. A shutter coordinated with the feed mechanism to expose the film during 
the periods of rest. 

The following quotation from my patent (written in the year 1891) may be 
of interest to you: 

"The purpose I have in view is to produce pictures representing 
objects in motion throughout an extended period of time which may be 
utihzed to exhibit a scene including such moving objects in a perfect and 
natural manner, by means of a suitable exhibiting apparatus. 

68 Transactions of S.M.P.E., September 1925 

''In carrying out my invention I employ an apparatus for effecting 
by photography a representation suitable for reproduction of a scene in- 
cluding a moving object or objects comprising a means, such as a single 
camera, for intermittently^ projecting at such rapid rate as to result in 
persistence of vision, im.ages of successive positions of the object or objects 
in motion as observed from a fixed and single point of view, a sensitized 
tape like film, and a means for so moving the film as to cause the successive 
images to be received thereon separately and in single-line sequence." 

The invention by me of this camera was in my opinion the egg of Columbus. 
By its means I had been able to secure as early as the summer of 1889 motion 
pictures on a long celluloid film representing exactly a scene as it would be ob- 
served by the eye with all of its details both as to background and as to objects 
moving with respect to the background. No such film had ever before been 
secured. No such camera for feeding a film intermittentlj' and making exposures 
during the periods of rest had ever before been made or suggested. 

After making my camera, the question then was, how shall the pictures be 
reproduced? It was obvious that they could be viewed directly throught a suitable 
magnifying lens or that they could be projected on a screen as had been done bj'' 
Muybridge and Marey in their classical work on the anah^sis of motion. 

The m.ost fruitful field immediately before m,e was the exhibition of the 
pictures by direct observation rather than by projection, because in the year 1890 
and for some time afterwards a very popular form of entertainment in this 
country was the so called slot parlor where phonographs were installed, ar- 
ranged to be operated by coin-controlled mechanism. It therefore occurred to 
me to start out with a device by which the motion pictures could be made use of 
in the m.any hundreds of slot parlors which were then doing a flourishing business 
in the United States. This resulted in the development of the peep hole kineto- 
scope in which the film was moved continuously by a coin started electric m_otor 
passing a magnifying lens of about tMO diameters; the picture was illuminated by 
an electric light below it and was observed through a slit in a shutter which 
exposed the picture when substantial!}^ in the optical axis of the lens. This gave 
an entirely satisfactory reproduction and anyone who remembers the old peep 
hole kinetoscope will I think agree with me that the results secured were remark- 
ably clear and natural. Several thousands of these first kinetoscopes were made 
and distributed throughout the country in the years following 1890 and many of 
them were exhibited at the World's Fair in Chicago in 1893. Hundreds of films 
were made fiom 1890 and even earlier, for which purpose the first motion picture 
studio was erected, known as the "Black Maria." 

I had always had in mind the projection of motion pictures on a screen 
even before the completion of vay first successful camera in 1889. As a matter of 
fact, it was our practice from the very first to test the character and qualit}' of 
films by projecting them on a screen by equipping the kinetoscope with a more 
powerful light and with a projecting lens. 

Of course such a device would not have been suited for the public exhibition 
of pictures bj^ projection owing to the insufficient light. For this purpose I saw 
that the successful projector should be based upon the principle of my camera 
wherein the periods of rest greatly e-xceeded the periods of motion of the film, 
thus -giving the opportunity for much greater illumination, or in other words 
making it possible to very greatly prolong the shutter opening. But in the early 

What Happened in the Beginning— Richardson 69 

days there was no demand for a projector; there were no motion picture theatres 
and even after projectors were made by me their introduction was slow. The 
competitive struggle between the motion picture theatre and the penny arcade 
lasted, as you will remember, for a good many years. 

In the year 1895 I had reached the conclusion, largely as the result of urging 
on the part of my agents, Messrs. Raff and Gammon, to design and manufacture 
a projector based upon the principal of my camera, feeding the film intermittently 
so as to secure satisfactory illumination. This work was well under wa}^ when 
early in the year 1896, Mr. Thomas Armat of Washington, D. C. brought to my 
attention a projector which he had invented and which he had exhibited in the 
previous Fall at the Cotton States Exposition at Atlanta. That exhibition, by 
the way, although technically successful, was a commercial failure. Any public 
interest in the possibiUty of motion picture projection was still dormant. Mr. 
Armat had worked out the details of the mechanism quite ingeniously and I 
concluded that the intermittent device which he had developed was more satis- 
factory than the one upon which I was working. I therefore arranged with him 
to use his type of projector, which was thereupon put on the market in 1896 as 
the Edison Vitascope and that machine Gater known as the Edison Projecting 
Kinetoscope) was \\-ith various modifications and refinements manufactured and 
marketed by me for many years thereafter. 

The foregoing comprises the essential facts in connection with my invention 
and development of the motion picture art. Of course m^uch of the success of the 
motion picture as we now know it has been due to many factors, such as the skill 
and artistic abihty of the directors, the technical skill of the camera men, the 
exhibition value of the scenarios, the genius of the actors, and the business judg- 
ment and coui'age of the manufacturers, distributors and exhibitors. 

But from a purely mechanical and technical standpoint the motion picture 
art was created when my camera was completed in the summer of 1889. That 
de\ice made it possible for the first time to secure a permanent photographic 
record of a scene inclucUng movement —something never before accomplished — 
and that de^dce also was the basis of and disclosed the principle used with the 
modern projector. In the latter respect it disclosed the two reels for storing and 
taking up the film after exposure, it disclosed intermittent mechanism for feeding 
the film step by step past the lens, it disclosed the feature of relatively long 
periods of rest with correspondingly short periods of motion, and it disclosed the 
shutter for exposing the film during the periods of rest. In a broad sense all that 
was necessary to convert the camera into a projector was to use a suitable source 
of illumination for the film and to enlarge the shutter opening to secure the 
maximum fighting effect. 

Yours very truly, 
(Signed) Thomas A. Edisox 

You will observe that 'Mv. Edison not only has covered the 
ground very thoroughly, but also he has cited certain official records 
in support of his statements. I am very sm^e there will be no shadow 
of a doubt in the minds of any of us but that ]\Ir. Edison has set forth 
only that which he believes to be the even and exact truth with 
regard to things not directly supported by corroborative evidence. 

70 Transactions of S.M.P.E., September 1925 

I have myself examined many records not incorporated in this 
paper, all of which corroborate what Mr. Edison has said. More than 
this I do not feel it right and proper to say, since, as I have stated 
there are some apparently conflicting claims, which I again respect- 
fully suggest that this Society take steps to try to harmonize. 

I next present for your consideration a statement by Mr. Thomas 
Armat, of Washington, District of Columbia. You will observe that 
the statements of Messrs. Edison and Armat agree throughout. 
There seems to be, so far as I am able to see, no conflict of claims with 
regard to the application of the old, well-known star and cam type 
of intermittent movement to the motion picture projector, in this 
country at least, but there was a bitter legal fight some years ago as 
to who invented what is known as the "Latham Loop," which is so 
very vital to intermittent projection. 

The only serious controversy existing today, so far as my under- 
standing goes, is with regard to who first projected life size motion 
pictures to a screen as we have them today, and it is this matter which 
I have suggested that this Society, through a committee, attempt to 
settle. I have other correspondence from Mr. Edison, Mr. Jenkins 
and Mr. Armat, together with certain items of evidence, which I will 
be glad to turn over to such a committee. 

Mr. Thomas Armat says : 

1870 Wyoming Ave. 

Klingle Road 
Washington, D. C 
April 4th, 1925. 

Mr, F. H. Richardson. 
516 Fifth Ave. 
New York. N.Y. 

Dear Mr. Richardson: 

I have your letter of recent date and have delayed answering it in order to 
get copies of certain patents which I am now mailing you under separate cover. 

These patents are Nos. 578,185 and 673,992 issued to me, and No. 586,953 
issued to C. F. Jenkins and myself. 

I am very glad indeed that you are taking the trouble to get at the facts in 
regard to the moving picture projecting machines covered by these patents, so 
many mis-statements concerning them having been pubhshed by uninformed, or 
misinformed, writers on moving picture history. 

My patent No. 673,992, applied for on February 19th, 1896, covers the 
/'Vitascope," and is no doubt the projector referred to by Mr. Edison, in his 
letter to you, as having been invented by me. 

What Happened in the Beginning — Richardson 


Nq. 673.992. 

(No Model.) 


fAppUcatlon flled r«b. i». I8e9.> 

Patented May 14. 1901. 

3 Sbeets-Sheet I 



y^f^ o o 

(^ctcjp. C^cc^^TcLC^^f i -J 

Fig. 1. Sheet No. 2 of U. S. Patent No. 673992 


Transactions of S.M.P.E., September 1925 

(No Model.) 2 Sheets— Sheet 2. 



No. 586,953. ' Patented July 20. 1897. 

ji -^^- .' 




&f<^. ^^t^al/^ 


Fig. 2. Sheet No. 2 of U. S. Patent No. 586953. 

What Hafp-pened in the Begmning — Richardson 

(No Model.) 




4 Sheets— Sheet 2 

No. 578,185 


Patented Mar. 2, 1897 


Fig. 3. Sheet No. 2 of U. S. Patent No. 578185 

74 Transactions of S.M.P.E., September 1925 

This patent although appHed for in February 1896 did not issue until May 
1901 for the reason that it was involved in a long Patent Office Interference 
proceeding. This is a proceeding for defining an invention and deciding who 
invented it. There were four claimants to this invention in this Interference to 
wit: Thomas Armat, Herman Casler, E. H. Amet and Woodville Latham. The 
applications were filed in the order named. The taking of testimony in such cases 
follows the rules laid down in courts of law and is very thorough. After taking 
volumes of testimony the case was decided in my favor by the Examiners-in- 
Chief, the Commissioner of Patents and finally, on appeal by Latham, by the 
Court of Appeals of the District of Columbia. The invention involved in this 
case was that of the "slack" or "loop" forming means in a projecting machines 
as set forth in claim 2 of my said patent 673,992. 

Some fifteen years after my machines covered by this patent were made and 
extensively exhibited and long after this Interference had been decided in my 
favor, certain claims were set up to the effect that a projecting machine of this 
character and covered by this patent had been made prior to the dates claimed 
by any of the parties to this Interference. It is sufficient to say that all such 
claims are absurd and untrue and were based upon false or mistaken testimony. 

Patent No. 586,953 was applied for by C. F. Jenkins and myself on August 
28th, 1895. The invention covered by this patent was the result of a series of 
experiments carried on under my direction after certain ideas of Mr. Jenkins 
had been tried out and proved to be valueless. These experiments extended over 
a period of about three months, from April to August 1895. The first and only 
place the machine of this patent was ever exhibited was in my office in this city 
in the month of August 1895. This was also the first exhibition anywhere of a 
machine embodying the principle covered by the claims of this patent. The 
machine was a mechanical failure and commercially valueless for the reason that 
in it we attempted to give a rapid intermittent movement to a large and' heavy 
kinetoscope sprocket. The claims of this patent however, if they could be sus- 
tained, had a certain strategic value in connection with my later and successful 
projecting machines. The claims covered broadly the principle of giving, in a 
projecting machine, an intermittent movement to the moving picture film so that 
each picture on the film was given a relatively long period of exposure, as set 
forth in detail in the claims. This patent was also involved in a Patent Office 
Interference proceeding. I have recently had occasion to go quite fully into the 
facts in this Interference and will be glad to go over them with you, but will not 
take the time now to do so. 

My patent No. 578,185 covers the so-called Geneva star type of intermittent 
movement as applied to moving picture machines. The claims are broad enough, 
as you will see, to cover this and all similar types of intermittent movements. 
The intermittent movement mechanism has been frequentl}^ referred to as the 
"heart" of the moving picture projector. This Geneva type of intermittent 
movement as you doubtless know, superseded all other forms soon after it was 
introduced in the fall of 1896, or thereabouts, and continues to be almost uni- 
versally used up to the present time. 

After I had produced a satisfactory projecting machine in the fall of 1895 , 
it of course became necessary to secure an adequate supply of moving picture 
films for use thereon. All films I had used for experimental purposes in 1895 

What Happened in the Beginning — Richardson 75 

were Edison films secured from the Columbia Phonograph Company who had an 
Edison Kinetoscope parlor in Washington. They, in turn, secured them from 
Messrs. Raff and Gammon of New York, who were exclusive agents for Mr. 

In December 1895 I started negotiations with Messrs. Raff and Gammon 
and shortly thereafter entered into a contract with them under the terms of 
which they were to supply Edison films for use on the "Vitascope" the name I 
had given the projector described in my patent No. 673,992, and the Edison 
Manufacturing Company were to obtain a certain number of these projectors 
from a model I gave them. 

Raff and Gammon wanted to use the Edison name in connection with their 
exploitation of the Vitascope, for obvious commercial reasons and for the addi- 
tional reason that they wanted to be assured of a continued supply of Edison 
films. Edison kinetoscope films were the only moving picture films obtainable 
anywhere in the world at that date. Mr. Edison had produced his kinetoscope 
and had pending patents covering his camera and the product of the camera, the 
moving picture film itseK. The moving picture film has been held by the Patent 
Office and the Courts to be an essential element in the moving picture exhibiting 
machine. I have frequently stated that, in my opinion, when Mr. Edison pro- 
duced his camera and film he did far and away more than anyone else ever did 
before or since, in the way of moving picture invention. 

Recently certain misinformed writers on moving picture history have 
credited certain individuals, whose activities commenced years after Mr. Edison 
had produced his camera, his film and his kinetoscope, with having "invented" 
or * 'discovered" moving pictures. 

To set up such a claim from twenty-five to thirty years after the inventions 
covered by the patents I have referred to were made is of course absurd, as an 
intelHgent search of the Patent Office records would disclose. 

The moving picture art, like many others, has been a matter of evolution 
in which many people have had a part, some directly and some indirectly. In- 
ventors and manufacturers in the art of instantaneous photography which had 
to be brought to a high state of perfection before moving pictures as we know 
them today became a possibility, as well as manufacturers of celluloid strips for 
carrying the highly sensitive emulsion for taking the pictures, all had an important 
part in the development of moving pictures, so that no one person can properly 
claim to have invented or discovered moving pictures. 

I have never set up any special claims for myself one way or the other but 
I feel that I can justly claim to have done my full share of what Mr. Edison left 
to be done in the way of developing or inventing moving pictures, and, in the 
matter of projecting machines, I think perhaps that the patents I have referred to 
may entitle me to claim that I did more than anyone else in the way of inventing 
the first successful moving picture projecting machine. 

Prior to the advent of such a machine the moving picture film was confined 
to the very narrow field of the peep-hole or direct view machine, where the pictures 
about the size of a postage stamp, were seen through a lens that magnified them 
but very slightly. 

76 Transactions of S.M.P.E., September 1925 

The patents whose numbers I have given were the first ones covering the 
essentials of the projecting machine, the machine that throws the pictures upon 
the screen. 

The foregoing, I believe, answers all of your questions. 

Yours very truly, 

{Signed) Thomas Aemat 

You will observe that the Jenkins and Armat patent was, as we 
all now know, not practicable. The "Vitascope," invented by Mr. 
Armat and patented by him March 2, 1897, has the regulation star 
and cam movement, which, somewhat to my surprise, is a one-pin 
movement. This was later changed by Mr. Edison to a two-pin. 
It was the change of the Edison two-pin movement into a one-pin 
which constituted Mr. Nicholas Power's first big improvement to 
the Edison projector. 

The "Vitascope" as designed by Mr. Armat was intended to 
handle a continuous band of film over a "spool bank." This was the 
way Mr. Edison first used it. Apparently there is no means provided 
for cutting the light off the screen while the film is in motion over 
the aperture, which presumably was one of the improvements added 
by Mr. Edison. Also, I see no apparent method for effecting a framing 
of the film, though probably there was some method employed to 
accomplish this important and very necessary function. 

In the year 1901 Mr. Armat patented an improved form of 
the "Vitascope," but what finally became of it I do not know. 

I next present for your consideration the letter and two photo- 
graphs sent by Mr. C. Francis Jenkins, in response to my request for 

C Francis Jenkins 
Frank H. Edmonds 
Lewis M. Thayer 


1819 Connecticut Ave. 

Washington, D. C. 

January 8th, 1925 
Mr. F. H. Richardson, 
646 West 158th Street, 
New York, N. Y. 
Dear Mr. Richardson: 

I am enclosing the two photographs you asked for, (1) an early portrait, 
and (2) a photograph of my first projection machine, the type now used in every 
theatre the world over. 

This machine was built in 1893, and repeatedly exhibited in 1893 and 1894, 
and is the projector referred to in "The Photographic Times" for July 6, 1894 

What Happened in the Beginning — Richardson 


which I am quite sure you can find in an}' of the large pubHc Hbraries in New 
York City, I know I found it recently in the National Library here. 

In the Baltimore, (Maryland) "Sun", of October 2, 1895, appeared an ac- 
count of the construction of three copies of this machine for the Atlanta Cotton 
States Exposition of that year. 

These machines were installed in a building, especially built therefor by my 
financier, Mr. Thomas Armat, the first motion picture theatre ever built exclusivelj^ 
for the purpose, the admission charged being 25c. Notices of this "marvelous 
exhibition" appeared in the Atlanta papers, and copied rather extensively else- 

That winter the original machine of which the Atlanta machines were 
copies, w'as exhibited before ths Franklin Institute (Philadelphia), and after the 
taking of much testimony for and against the claim that I was the inventor, the 
Elliott Cresson gold medal was awarded by the Institute to me. 

It may interest you to know that within a few weeks, that is, before the 
next S.M.P.E. meeting, w^e expect to give public exhibitions of motion pictures, 
and performances from living subjects, transmitted by radio from our studio to 
private homes here in the city, a perfection of the present apparatus of daily 
demonstrations in our laboratory here. 

Sincerely yours, 
CFJ/sla {Signed) Jenkins 

Fig. 4. The Phantoscope. Invented by Mr. Jenkins and used in 1893-94. 

You will observe that both projectors shown have the well known 
"beater" type of intermittent movement. You will also observe that 
the first mechanism (Fig. 4) apparently has no means for shutting 
the Ught off the screen while the film is in movement. There is no 
lamp house at all, and what seems to be a cell, which probably was 


Transactions of S.M.P.E., September 1925 

filled with alum water to absorb a portion of the heat, is in front of the 
condenser. There is an upper sprocket, and a lower sprocket, driven 
by a worm gear, the upper sprocket being chain driven from the shaft 
of the lower one. These sprockets are apparently about three inches 
in diameter, and of a width to take film of approximately, if not 
exactly, the present width and perforation. Mr. Jenkins' claim is that 
this projector was made and used by him to project life size motion 
pictures in 1893 and 1894. The means for driving the mechanism is 
not apparent. 

Fig. 5. The "Atlanta Exhibition" machine. One of three copies of the Phanto- 
scope taken to the Atlanta Cotton States Exposition. 

The second picture (Fig. 5) is of the "Phantoscope," which is the 
projector Mr. Jenkins advises was made for use at the Atlanta 
Exposition. Apparently it is of the same general type, but an im- 
provement on the one shown in the first illustration. There seems to 
be no upper sprocket shown. The cell in front of the condenser in 
the first projector is absent in this one. There is some attempt at in- 
closing the arc, though the lamp itself is still outside. 

What Happened in the Beginning — Richardson 79 

The next statement is in the form of a letter from Mr. George 
Eastman to the author of this paper. I am very sure you will be 
deeply interested in what it contains. Mr. Eastman has, at my 
request, personally prepared it with intent that it become a part of the 
records of this Society, and as such a permanent, official record of 
his activities in the matter of discovering flexible film and its 
application to motion pictures. Mr. Eastman says: 


Rochester, N. Y. 

March 18th, 1925 
Mr. F. H. Richardson, 

New York City, 
Dear Mr. Richardson: 

In reply to your letter of March 2nd, addressed to our Mr. Blair, asking 
for a statement in regard to my connection with motion picture film, to be made 
a part of the records of the Society of Motion Picture Engineers, I am writing 
this letter. 

1 have read Mr. Edison's statement of January 24th and am in full accord 
with the reference which he makes to me. 

About the year 1883 or 1884, in connection with William H. Walker, I 
engaged in an effort to create a system of film photography. Mr. Walker was a 
skilled mechanic and had had some experience in manufacturing cameras. I was 
engaged in the manufacture of dry plates and had had experience in the making 
and handling of photographic emulsions, as well as some mechanical experience. 

On looking over the ground we found that there were three things necessary 
to be accomplished: 

1st. To find a suitable flexible support to take the place of glass. 
2nd. To devise a method of applying emulsion to it, and 
3rd. To create a practical mechanism for exposing the sensitive flexible 
support in the camera. 

Walker and I worked together on the mechanical problems, while I tried to work 
out the photographic and chemical side of the enterprise. The broad idea, of 
course, was not new. An exposing mechanism, called a "roll holder," for sensitized 
paper had been made as early as 1854, the year that I was born. Warnerke, in 
about 1875, made a roll holder and a film, the latter consisting of paper coated 
with collodion emulsion. The image was stripped direct from the paper after 
exposure and development. His attempt to create a system of film photography 
was a failure and the field had been practically abandoned at the time Walker 
and I began. We soon worked out a practical roll holder. A machine for coating 
paper in bands 8 or 10 ft. in length, for the carbon process, was in existence. We 
devised a machine for coating paper continuously. I invented a film, known as 
"Eastman Stripping Film"; filed an application for patent on March 7, 1884, 
and the patent was issued October 14, 1884. This completed a practical system 
of film photography. A company, The Eastman Dry Plate and Film Company, 
was formed and the enterprise started in 1885. It was successful from the start 
but the use of the film was hampered by the necessity of sending it to the Company 

80 Transactions of S.M.P.E., September 1925 

for development because the development and finishing of the negatives was too 
compHcated for the amateur, or even the dealer, to accomplish. The film con- 
sisted of a strip of paper first coated with soluble gelatine and afterwards with the 
sensitive emulsion. After the film had been exposed in the roll holder it was de- 
veloped and then squeegeed down on to a glass plate which had previouslj^ been 
coated with a thin solution of rubber. This held it in a rigid position while the 
paper was dissolved off by hot water, leaving a very thin image on the glass plate. 
This had to be reenforced by a sheet of moistened gelatine. When dr}' the re- 
enforced image could then be pulled off from the glass plate. This produced a 
negative which was very similar to the film of the present day. There were other 
objections to this process beside the complications. For instance: The time 
required to dry the gelatine sheet used for the backing; and the fact that the image 
sometimes was affected b}^ the grain of the paper offsetting. It was quite obvious 
that what was needed to make a perfect substitute for the glass plate process w^as 
a substance which had the properties of glass except its rigidity and fragility. 
Transparent celluloid had already been used as a substitute for glass in making 
single negatives but no way was known of producing it in sheets thin enough and 
long enough to use in a roll holder. After we got started with the stripping film I 
made many experiments to produce long sheets of transparent material, using 
cellulose nitrate "soluble cotton", which is the chief constituent of celluloid. I 
used the only solvents known in photography at that time, namely grain alcohol 
and ether. A mixture of these solvents would only dissolve about 10 per cent of its 
weight of the cellulose nitrate and this solution, when coated on glass, gave too 
thin a film to be of any use. I tried building up a thicker film by using successive 
coatings of this solution (known as "collodion") and rubber but I could not get 
a thick enough film to be practical. In the meantime, failing to succeed in pro- 
ducing this ideal support, I began to experiment in replacing the sheets of gelatine 
used for backing the stripping film with a varnish to overcome the objection of 
the slow drying. One day a young assistant whom I had assigned to this job 
came to me with a bottle of varnish and a glass plate bearing a stripping film 
negative w^hich had been varnished and partially stripped from the plate. He 
said he had found just what we were looking for. I asked him what the varnish 
was composed of and he said: "Wood alcohol and soluble cotton." It was very 
thick, like separated honey. I saw at once that it was the solution which I had 
been looking for to make film base and immediately began to devise apparatus 
for producing film by drying the varnish on long strips of plate glass. We at 
once fitted up a small factory with tables 100 ft. long, having glass tops of the 
longest sheets of plate glass we could find, with the joints cemented together, and 
began to make the first practical transparent film in rolls that was ever put on 
the market. This was in August, 1889. 

While we were engaged in fitting up this factory I received a call from a 
representative of Mr. Edison's who told me of Mr. Edison's experiments in motion 
pictures and how necessary it was for him to have some of this film. The idea of 
making pictures to depict objects in motion was entirely new to me but of course 
I was much interested in the project and did my best to furnish him film as near 
to his specifications regarding fineness of grain and thickness as possible. As far 
as I know the film we furnished him then, and from time to time later, was satis- 
factory. In the years during which the motion picture industry has been develop- 

What Happened in the Beginning — Richardson 81 

ing we have made many improvements in the way of fineness of grain, photo- 
graphic quahty, and uniformity, but the film made today is substantially the 
same as the first film furnished Mr. Edison. 

So far as I can recollect all the experimental film that was furnished Mr. 
Edison was negative film. Special film for printing positives was not made until 
about 1895. 

The new film was a success for amateur purposes from the moment it was 
offered to the pubhc. The use of film has superseded glass plates for amateur use 
for many years past; and of late years has been replacing them for all professional 
uses as well. 

The support, instead of being made on glass tables as at first, is now cast on 
the surface of great nickel plated wheels which run continuously night and day, 
week in and week out. One of these wheels, of which we have upwards of fifty, 
produces 25 times as much as the whole of our fir^t factory. The base is turned 
over to the sensitizing department in rolls 41 inches wide and 2,000 feet long and 
is so accurately made that it does not vary over one-four thousandth of an inch 
in thickness. Of course only a part of this product is for motion pictures. 

Yours very truly, 

{Signed) George Eastman 

It is understood that the above statement will be incorporated in the 
records of your Society as an unaltered whole. 

The last personal statement I shall present is one by Mr. Albert 
E. Smith, President of the Vitagraph, and one of the two men who 
originally formed that company in March, 1897. Unfortunately, 
when I saw Mr. Smith he was about ready to leave for the west coast, 
and could only take time to dictate a very brief statement. 

The information about the "Idoloscope" is interesting, also, 
you will note that Mr. Charles Webster, whose photograph I will 
show you later, and who was the projectionist the second night 
Thomas A. Edison saw motion pictures in their present form, was 
one of the firm known as the International Film Company. 

I think but few of us knew that William T. Rock did not join the 
Vitagraph until two years after it was organized. I know I always 
had the idea myself that it was he who organized the company. 

The thing called by Mr. Smith the "setting device," was what 
we now know as a "framer." Mr. Smith's explanation of its in- 
vention was that the film would "creep up" out of frame in the 
friction type of projector, and the framer was designed to overcome 
that fault, or to neutralize it, rather. 

Mr. Smith says: 

82 Transactions of S.M.P.E., September 1925 

Albert E. Smith, President 



E. 15th St. & Locust Ave. 


April 13th, 1925, 
Mr. F. H. Richardson, 
646 West 158th Street, 
New York, N. Y. 
Dear Mr. Richardson: 

The following statement covers dates of happenings of early items of in- 
terest in the history of the Vitagraph Company, which I trust will be of use to 

The Idoloscope was brought out in 1896. It was a special machine, using a 
special film, in the camera of which the film ran continuously and in which the 
film was rendered optically stationary, by the aid of a slot in a 360° shutter. 

The film was first projected with a machine in which the film ran contin- 
uously, but later was projected with the aid of a Pitman or Beater movement 
which Beater movement was later incorporated in the camera. 

The film and apparatus of the old Idoloscope Corporation was purchased 
by Mr. J. Stuart Blackton and Mr. Albert E. Smith in the early part of 1897. 

The International Film Co. was owned by Messrs. Webster and Kuhn. 
They operated from 1896 to 1898. 

The Vitagraph was organized by Mr. J. Stuart Blackton and Mr. Albert 
E. Smith in March, 1897. 

Mr. William T. Rock joined Vitagraph in the summer of 1899. 

Vitagraph's first projector was built by Mr. Albert E. Smith in 1896. It 
had an intermittent friction movement, and the setting device that was incor- 
porated in all later Vitagraph machines and was copied on all Edison projecto- 
scopes and was imitated by most other projectors, was the same setting device 
that was devised on the original Vitagraph projector in 1896. The non-flicker 
shutter was devised by Mr. Albert E. Smith, and used on Vitagraph machines 
in 1898. 

The first pictures by electric light were taken in 1899 by Mr. J. Stuart 
Blackton and Mr. Albert E. Smith, at the old Manhattan Theatre in New York, 
which was loaned for the occasion by William A. Brady. Upon demonstrating 
the success of photographing by electric light, Mr. Brady then contracted with 
Mr. Blackton and Mr. Smith, to photograph pictures of the Fitzsimmons-Jeffries 
Fight at the Coney Island Sporting Club, in 1899. 

Ipr I Unfortunately, the cyHnder head of the engine of the special plant, which 
was installed at Coney Island to furnish the current for this operation, blew out 
at the start of the fight, and therefore, the entire fight was never photographed. 

The enlargement over Mr. Rock's desk in the photograph showing the 
early Vitagraph Office, is an enlargement of one of the moving pictures taken of 
the Fitzsimmons-Jeffries Fight. 

The first picture was made by Mr, J. Stuart Blackton and Mr. Albert E. 
Smith' on the roof of the Morton Building, No. 140 Nassau Street, in the fall of 

What Happened in the Beginning — Richardson 83 

1897. It was a short comedy picture, about 45 feet in length, and was called 
"The Burglar on the Roof." 

The average length of pictures at this period, ran from 40 to 75 feet. 

The early pictures of the Vitagraph Company were either topical, that is, 
scenes of every-day occurrence, comedy, or magical pictures — the magical 
pictures being what were known as the "stop-motion" variety, that is to say, the 
action would be carried to a certain point, where the director would call "stop." 
Everyone then would hold the position that they happened to be in at the moment. 
Some change would then be made in the development of the action, that is to say, 
a character's coat might be taken off and laid on the floor, and when this action 
was carried out, the director would give the word "go." The camera would start 
to grind, the characters would start further business, until they again received 
the word "stop," when some other change would be made. 

When the negative was finally cut and edited, the effect of this particular 
business would be that, during the course of the action, one of the character's 
coats would suddenly fly off onto the floor. 

All the magical effects were instantaneous happenings, produced somewhat 
after this fashion and along these lines. 

The first "stop-motion" picture of this nature produced by Vitagraph, 
which made a big hit throughout the country ,was a "Visit to the Spiritualist," 
in which all kinds of mysterious things happened, the same being brought about 
by the above described method. 

The foregoing relates to pictures taken prior to 1900. 

The first animated cartoon was made by Mr. J. Stuart Blackton and Mr. 
Albert E. Smith, in the year 1903. 

The first director engaged by Vitagraph was Mr. G. M. Anderson, who 
joined the Vitagraph forces in 1904. He later became the partner of Mr. George 
K. Spoor in the Essanay Film Producing Company, Chicago. 

Florence Turner was the first Vitagraph star, and I believe the first film 
star. She joined Vitagraph in 1905, becoming popularly known as "The Vita- 
graph Girl." 

Very truly yours, 
A. E. Smith, President 

I shall now show you various pictures, some of which are my own 
property and some of which have been loaned to me. Many of them 
are very valuable, because of the fact that no known duplicates exist. 
Mr. William Reed, Motion Picture Projectionist at Atlantic City, 
New Jersey, is owner of some of the most rare and interesting ones. 

Let me say that Mr. George Eastman and Mr. Thomas A. 
Edison are two of the great men on earth — men whose names and 
whose works will live so long as the history of our time shall last. 

Both Mr. Edison and Mr. Eastman were pioneers in the very 
forefront of the motion picture industry. Both Mr. Eastman and 
Mr. Edison have told you the story of what they did in the early days. 
It would be presumptuous for me to dilate upon the tremendous 

84 Transactions of S.M.P.E., September 1925 

influence these two gentlemen have had upon the perfection of the 
thing which has come to be the most widely patronized and the most 
keenly enjoyed form of public amusement the world has ever known. 
Next I present (Fig. 6) to you a gentleman who needs no intro- 
duction to the Society of Motion Picture Engineers, because C. 
Francis Jenkins was chiefly instrumental in bringing about its forma- 
tion and in literally nursing it through its first years of life. 

Fig. 6. Mr. C. Francis Jenkins. 

Had C. Francis Jenkins done no other thing for or in the motion 
picture industry than to form this Society, surely that one act would 
be quite sufficient to write his name upon the Roll of Honor of the 
industry as a man who did really worthwhile things. 

The next picture (Fig. 7) is that of WilHam T. Rock, one of the 
pioneers in both the production and exhibition end of the motion 

What Happened in the Beginning — Richardson 85 

picture industry. It was he, who, together with his partner, Mr. 
Wainwright and Wilham Reed, projectionist, opened Vitascope Hall, 
corner of Canal Street and Exchange Place, New Orleans, Louisiana, 
in June, 1896, which was the first theatre used strictly and exclusively 
for the exhibition of motion pictures of which I have been able to 
discover tangible evidence — any evidence other than the personal 
statements of various individuals, which same I have invariably found 
to be more or less contradictory. I shall present to you a photograph 
of this theatre and of its programme before I have finished. 

Fig. 7. The late William T. Rock, President of the Vitagraph Company of 
America from the time it was organized until his death some years ago. 
Mr. Rock and his partner, Mr. Wainright, opened the Motion Picture 
theatre in New Orleans, in the year 1896, which was the first theatre, of 
which visible evidence still remains, devoted exclusively to motion pictures. 
Mr. Rock was, during his lifetime, one of the most widely known men in all 
the motion picture industry of that day. 

Mr. Rock, who was popularly known throughout the industry 
of that day as 'Top" Rock, joined the Vitagraph Company in its 
early days (1899) and, up to the time of his death a few years since, 
was its president. He was in many ways a picturesque character, an 
excellent business man, and very capable in the matter of forming 
correct judgment as to the amusement value of various things. He 
loved diamonds, his collection of them being famed throughout the 
entire industry of that day. The picture selected is somewhat in the 
nature of a "freak," but it nevertheless is a most excellent likeness 


Transactions of S.M.P.E., September 1925 

of Mr. Rock, as the writer remembers him. It was taken during the 
last years of his life. 

The next picture (Fig. 8) is that of William Reed (left) and 
Charles Webster (right). It was Charles Webster who acted as pro- 
jectionist on the second evening that Thomas Edison witnessed the 
projection of life size pictures on a screen by means of Mr. Armat's 
"Vitascope" projector. On the first evening Mr. Armat himself 
projected the pictures. That was the first time Mr. Edison ever saw^ 


Mr. William Reed (left) and Mr. Charles ^Yebster (right). 

motion pictures projected to a screen at fuU life size, though at that 
time he was himself working on a projector designed to do that very 

WilHam Reed was the man who left a position with Messrs. Raff 
and Gammon w^here he was ''keeping tab" on Edison peep-hole 
Kinetoscopes in Boston and vicinity, and went with Messrs. Rock and 
Wainwright to New Orleans, Louisiana, in the spring of 1896, w-here 
he acted as motion picture projectionist, using an Armat " Vitascope," 
which same had then been taken over by Mr. Edison. 

After having filled an engagement in a New Orleans park, Messrs. 
Rock and Wainwright opened "Vitascope Hall," as will be hereinafter 
set forth. 

What Happened in the Beginning — Richardson 


Mr. Reed was the guest of this Society at its Atlantic City dinner, 
in May, 1923. He has requested that I convey to you his fehcitations 
and earnest good wishes. He has projected motion pictures con- 
tinuously from the time he started in New Orleans in 1896 up to the 
present time. He is today projectionist at the new^ Palace Theatre in 
Atlantic Citj^, New Jersey. 

WTiile it cannot be said that Air. Reed was the first man to 
project motion pictures, he was, nevertheless, the projectionist in the 


Mr. Nicholas Power. 

first strictly motion pictm-e theatre of w^hich we have printed, 
authentic record, and certainly his record entitles him to be hailed 
as the Dean of Motion Picture Projectionists. 

Nicholas Power has passed to that bourne whence no traveler 
ever returns, into the shadows of which so many of the pioneers of 
the industry have already entered. Next to Mr. Edison himself 
Mr. Power was the first man to manufacture motion picture pro- 
jectors on a commercial scale for use in the United States of America 

88 Transactions of SM.P.E., September 1925 

and Canadian America. In fact, so far as I have been able to find out, 
for some time after Mr. Power himself began manufacturing pro- 
jectors the Edison Company was his only rival in that field. Certain 
it is, that the Edison Company and Mr. Power were the only ones 
who put out any considerable number of projectors in the very early 
days of the industry. 

Just how Mr. Power, who I have been told, was a dabbler in real 
estate dealings before he took up projection, first came to take up 
projection I have not been able to ascertain. His family refused to 


Fig. 10. The Power's Peerless Projector. 

give any information on the subject. Either in the fall of 1896 or the 
spring of 1897 he was acting as projectionist at the Koster and Bial 
Music Hall, on Twenty-Third Street, near Sixth Avenue, New York 
City. Afterwards he was projecting pictures at a vaudeville theatre 
in Brooklyn. The story is that One day when he took down the 
intermittent movement of his Edison projector, he was unable to 
get it back in time for the evening show, had a go-round with the 
theatre manager and quit — either voluntarily or "by request." 

What Happened in the Beginning — Richardson 


Fig. 11. The Power's No. 1. 


Transactions of S.M.P.E., Septe7nher 1925 

Shortly thereafter he leased a room on the third floor, 117 
Nassau Street, where he started a repair shop for Edison projectors. 
Soon he conceived the idea of making changes in the mechanism of 
the projectors. I am told that his first improvement was the changing 
of the then two-pin Edison Geneva movement to a one-pin. He then 
added other changes and improvements of his own, and soon came 
out with what he called the Power's Peerless Projector, very few of 

Fig. 12. The Power's No. 2. 

which were actually made and sold. In the accompanying picture, 
(Fig. 10), notice the sack for catching the film after projection. This 
is a very genuine relic of the distant past of motion picturedom. 
I very much doubt if there is another picture of this projector in 

Shortly after the advent of the 'Tower's Peerless," which must 
have come out some time in either 1897 or 1898, Mr. Power brought 

What Happe7ied in the Beginni7ig — Richardso7i 


out his 'Tower's No. 1" projector, which was followed by the No. 2, 
No. 3, No. 4 and No. 5 models, all of which appeared between 1897 
or 1898 and 1907, in which latter year the No. 5 appeared, it being 
the first approach to a really high grade projector mechanism in 
general use up to that time, except that the Motiograph had appeared 
shortly before, and George K. Spoor, of the Essanay Producing 



Fig. 13. The Power's No. 3. 

Company had put out a limited number of "Kinedrome" projectors, 
which were distinctly high grade mechanisms, as also were the 

During the first ten years of the industry, or up to about 1907, 
the only projectors having anything like a general use were the 
Edison, the Power, the Vitagraph, the Lubin, the Selig and (around 
Chicago, Ilhnois, only) the Motiograph, the Spoor Kinedrome and 


Transactions of S.M.P.E., September 1925 

r>-'%?#"ai l i^ 

What Happened in the Beginning — Richardson 


a claw-iiio\'ement projector made by a man named Pink, called the 
"Viascope." I have been unable to ascertain the exact dates at which 
these various projectors appeared. Except for the Powers and the 
Motiograph (The Simplex did not come into the field until about 
1911) they have all entkely disappeared, though being permitted to 
rummage tln^ough the ''morgue" of the Nicholas Power Company, 
examples of several of their mechanisms were discovered, covered 
with the dust and grime of manv vears. Through the kindness of the 

Fig. 16. The Edison Spoolbank projector. In one, the film is in a roll. The reels 
were supplied -w-ith the outfit. In the other are two views of the Edison 
Spoolbank Projector. Xote the diminutive size lamp house and how the 
film runs in a continuous l^and over the banks of spools. 

Power's Company I secured photographs of these mechanisms, which 
will, I am sure, interest you. I will show them to you a little later. 
I show you (Fig. 16) the famous Edison "spoolbank projector," 
of which you doubtless all haA'e heard, and many have wished to see. 
The photograph of this rehc came into my possession as technical 
editor of the Moving Picture World some years ago. By looking closely 
you may be able to trace the path of the film, which was in the form 


Transactions of S.M.P.E., September 1925 

Fig. 17. The Edison Spoolbank Mechanism. 

What Happened in the Beginm'ng^Bi chard son 


of an endless band. The "spoolbank" was merely a device to permit 
of using a band of film having greater length than could be used 
without it. The two upper views are two views of the same projector, 
while the lower one shows it, minus the spoolbank and fitted to use 
an upper reel, which same you may see is merely a core, or hub, with 
four projecting spokes on either side, to hold the film roll in position. 

Fig. 18. The Edison "Exhibition Model" projector. 

Notice the diminutive lamp house, and that the lamp mechanism was 
located entirely outside of it, only the long, flimsy carbon arms 
extending into its interior. Notice also how the lamp house sets up 
on a stand to bring the condenser in line with the projector aperture. 
The rheostat is, you will observe, well encased in a sheet metal cover. 
In Fig. 17 you see the mechanism of the Edison spoolbank pro- 
jector. It is the same general style, with its wooden frame, to which 
Mr. Edison clung, with slight variations, for many years — until 
about 1907. 


Transactions of S.M.P.E., September 1925 

In Fig. 18 3^ou see Mr. Edison's final perfected projector. Very 
soon after it was finished, and before it was placed on the market, 
Mr. Edison decided to abandon the making of motion picture pro- 
jectors, which he did, so that the "Super" never actually came on 
the market at all. 

Fig. 19. The Edison "Model B" Projector. 

The only model of projectors Mr. Edison ever placed on the 
market was the Edison ''Exhibition Model," of which many thou- 
sands were sold. It had, as you maj^ see, a wooden frame. It had an 
''inside shutter," the interrupter blade of which was perforated. 

The Model B came out about 1907 or 1908. It had a metal frame, 
but aside from that change and several improvements, it clung closely 
to the old Edison style of projector. 

What Happened in the Beginning — Bichardsov 


Motiograph Early Models 
I present to j^ou (Fig. 20) a pictui'e of the JModel No. lA Motio- 
graph, its predecessors the No. 1, No. 2 and No. 3 Optograph and 

NO. I A 


Fig. 20. Motiograph Early Models. 

the DeLuxe model Motiograph of today. Aside from the Spoor 
Kinedrome, the ^Motiograph was the fu'st closely built projector 
mechanism given us. It was the invention of ]\Ir. A. C. Roebuck, a 


Transacticns of S.M.P.E., September 1925 



What Happened in the Beginning — Richardson 


member of the Society of Motion Picture Engineers, and a man we all 
know well. AATiat you may not have known, however, is that he was 
the original Roebuck of Sears, Roebuck & Co., the famous mail order 

Fig. 21 is of the old Selig projector mechanism. Observe the 
small crank and the chain upper sprocket drive. It had a claw 
movement, commonly termed, at that time, a "finger feed." It was 
great on ripping out the divisions between sprocket holes. 




Fig. 23. The "Lubin Cineograph," discontinued about 1910. 

In Fig. 22 is shown another claw movement projector mechanism, 
which was very popular in and about Chicago, Illinois, about 1907 
and 1908. It w^as roughly built, but gave results considered very 
good in that day. 

Lubin Projector 

In Fig. 23 is shown the projector mechanism put out by Siegmund 
Lubin. It disappeared finally about 1912. It was crudely constructed 

100 Transactions of S.M.P.E., Septemher 1925 

and never very successful, though at one time rather widely used in 
the city of Philadelphia and territory immediately adjacent thereto, 
also it was used somewhat in other eastern territory. 

A Stranger 
This picture (Fig. 24) is made from a photograph which has been 
in my possession for a long while. Evidently it is an early type, and 
I have suspected it was one of Mr. Power's first efforts toward chang- 

FiG. 24. A Stranger. 

ing and improving the Edison projector. Note the framing device 
which raises the gate bodily a short distance by means of a slow-acting 

Amet Magniscope 
This picture (Fig. 25) is of the Amet Magniscope, a projector 
invented by a man named Amet, who now is located in Mobile, 
Alabama. At the time he evolved this mechanism he lived near 

What Happened in the Beginning — Richardson 101 

(^CLX j/ tLi -^-^^ 

Fig. 25. The Amet Magniscope. 

■^ _:^^"t 




Fig. 26. Old Films 


Transactions of S.M.P.E., September 1925 

Chicago, Illinois. Its intermittent movement was of the clutch trip 
type, hence, enormously noisy and quite impractical. It projected 
nine pictures per turn of the crank. The picture is only of interest 
as showing one of the early efforts to evolve motion picture projectors. 





/? F£VJ r/lLiJA/is' ^ 
6PiM£ YB]lsl 

'TIN' n&S'L 

Fig. 27. Old Type Films. 
Here is a projector mechanism which was considered one of the best and 
most popular no longer ago than 1912. Thousands of them were then in use. 
How many of you can name it? I had the engraver remove the name plate in 
making the engraving. 

Old Type Film 

1 show you in Fig. 26 some of the early types of fibn. I have 

lost the data connected with the one to the right. Note the wide 

spacing between the pictures and the round, queerly placed sprocket 

holes. ^ The Veriscope film and projector were made especially to 

What Happened in the Beginning — Richardson 103 

"take" the Fitzsimmons-Jefferies prize fight. It was, so far as I know, 
never used for anything else. 

Old Films 
Some months since I pubHshed a picture of an Edison Model B 
mechanism, asking how many projectionists could identify it. One 
man sent the drawing shown in Fig. 27 in addition to the picture of 
the mechanism. It is distinctly interesting. I venture many of you 
had almost entirely forgotten some of these one-time popular films. 

Fig. 28. Vitascope Hall. 

Vitascope Hall 
I now present a photograph of "Vitascope Hall," opened by 
Messrs. Rock and Wainwright as a strictly motion picture theatre, 
in June 1896. Its location was the corner of Canal Street and Ex- 
change Place, New Orleans, Louisiana. They showed, among other 
things, the "May Irwin Kiss," "Waves of Dover," also a lot of short 
scenic stuff. Admission was ten cents. For ten cents additional 
patrons were permitted to peek into the "projection room" and for 
another ten cents they were presented with one frame of old film. 

104 Transactions of S.M.P.E., Septemher 1925 

The projector used was the Armat Vitascope, then being pro- 
duced by Thomas A. Edison, and, for business reasons, called the 
"Edison Vitascope." That last is on the authority of projectionist, 
Reed, who had it direct from Mr. Rock, who himself purchased the 

The theatre was a store room fitted with a screen, wooden chairs, 
an enclosure for the projector, a ticket booth and a name — Vitascope 




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Fig. 29. Vitascope Hall Program. 

From the Bill of the Theater at 623 Canal Street, New Orleans, La., in 
the fall of 1896, of which you have been show^n a photograph. Take note of the 
adm.ission price, also the reference to "Edison's Vitascope" and "Edison's 

Hall. It seated about four hundred people. In the photograph you 
see its operators, Messrs. Rock and Wainwright, standing in front, 
together with its projectionist, William Reed. Mr. Rock is at the 
extreme right, with Mr. Wainright next to him. Mr. Reed is at the 
extreme left. The names of the others are unknown. You will observe 

What Happened in the Beginning — Richardson 


that "Li Hung Chang" was the bill on the day the photograph was 

Vitascojje Hall Program 
Here, gentlemen, is the printed program of that little theatre 
of far-off days. Doors open 10 to 3 and 6 to 10. 

Letter of Raff and Gammon 
Messrs. Raff and Gammon, whose office was in the Postal 
Telegraph Building, 253 Broadway, New York City, were agents for 
the Edison Phonograph, and sole agents for the Edison peep-hole 

Raff ^ 6aitittion 




Cbe Vltascope 




Postal Teleeraph Buildins:, 253 Broadway 

Removed tn 43 W. ?.8th St. 

N. C. R. 

Harry Brooks, Esq. , 

2995 Washington St. 

Roxbury, Mass. 
Dear. Slr:- 

hlSlt 1« thf? J° Massachusetts has been sold, and 3f you wish to ex/ 
KJiJlhi^ ^?Q l^^^l' r"^ \^^^ ^'^''^ ^° address the purchaser. Mr. P. W. 
Klefaber. 419 New Market St.. Philadelphia Pa. , x. . «. 

««.« '^?''i'**i® ^^^'^ ^° ^®^^ y°^ *^® ^^S^* to ^ny state remaining 
S^h'tr^ecur^ tS^hTri^h?^' ^^'^'^' ^"^ ^°^ ^^°^^^ -^ ^--P^^^ ^^ ^- 

Very truly yours, 

Fig. 30. Letter from Raff and Gammon. 
This letter was written May 9, 1896, just about the time Mr. Edison had 
the Vitascope projectors ready for the market in considerable numbers. The 
note in ink was presumably made by Mr. Brooks. This letter is especially inter- 
esting as showing the avidity with which state rights were taken up. 

kinetoscope. It was this firm who were responsible for Mr. Armat's 
invention being called to the attention of Mr. Edison. They heard of 
it, Mr. Gammon went to Washington and witnessed its performance, 


Transactions of S.M.P.E., September 1925 

was so impressed with its apparent possibilities, even in its then very 
crude form, that he hastened to lay the matter before Mr. Edison, 
and plans were laid for a demonstration of the projector at the 
Edison laboratories. Evidently the demonstration was satisfactory, 
for arrangements were entered into immediatelj^ between IVIr. Armat 
and Mr. Edison to build the projectors at the Edison plant. Due to the 
commercial value of Mr. Edison's name, it was decided it would be 
best to use it in connection with the projector, which thus became the 
"Edison Vitascope." 


WHERE r~~ '"?^ HIS 

FIRST ^""""" ^ 

Fig. 31. The Black ^laria. 

Soon after this IMessrs. Koster and Bial, who operated two music 
halls, one on West Twenty-Third Street, New York City, and one at 
Broadway and Thirty-Fourth Street, where the Macy Department 
Store now stands, booked the "act" (life size motion pictures) for 
theh Thirty-Fom^th Street house, paying the sum of five hundred 
dollars per week therefor. I might add that as soon as Oscar Hamer- 
stine saw the "act" he offered one thousand dollars a week for it, but 
his offer was refused because Messrs. Koster and Bial had it under 
contract. Keith also tried to secure it for his Fom^teenth Street 
Theatre, but failed for the same reason, whereupon he at once pro- 
ceeded \o import Lumiere cinematographs, which arrived in July, 

What Happened in the Beginning — Richardson 107 

1896, together with men to act as projectionists. Mr. F. Keith had 
an Edison Vitascope in his Boston, Providence and Philadelphia 
theatres early in ^lay, 1896. 

The fii'st show at Koster and Bial's consisted in "Anabella in 
the Butterfly Dance," "Shooting the Chutes at Coney Island," and 
the "Waves of Dover," the latter beitig a surf pictui'e made by a 
man named Paul, in London, England. James H. AMiite and P. L. 
Waters, were projectionists on the night the "act" opened at Koster 
and Bials. 

Fig. 32. The Vitagraph Office. 

The Black Maria 
In Fig. 31 is shown a photograph of what was the first strictly 
motion pictm-e development plant in the enthe world. It was a frame 
structure covered with black tar paper, and the Edison force quickly 
christened it the "Black INIaria," which name clung to it and has been 
passed down to us as histor3\ It was the building erected to develop 
motion picture fihns for use in the Edison peep-hole kinetoscope, but 
was used for a time to develop films for use with the Vitascope. 


Transactions of S.M.P.E., September 1925 

Mr. Edison still has the negative of this picture, from which he 
was kind enough to permit the making of a print for this paper. 
I feel that I cannot too strongly stress the advisability and desirability 
of this society, possibly acting in conjunction with others identified 
with the industry, devising some method by means of which such 
relics of early days may be collected and preserved in as nearly as 
may be a permanent way, for the benefit of posterity. I am sure that 
even so comparatively short a while as one hundred years from now 
such things will have value beyond all computation. 

Fig. 33. The Vitagraph Development Plant in 1897. 

of today. 

Contrast it with those 

Next I present (Fig. 32) two photographs, one of the office of 
the Vitagraph Company of America in its early days and one of the 
first development plant of the same company, the latter picture 
was taken in 1897. 

In the first picture the late Mr. William T. Rock, then president 
of the Vitagraph Company, is seen seated at his desk at the left. Over 
his desk is an enlargement of one frame of the Fitzsimmons-Jefferies 

What Happened in the Beginning — Richardson 1 09 

prize fight, taken by the company. At the right is J. Stuart Blackton, 
and in the center Alfred E. Smith, who became president of the 
Vitagraph Company after the demise of Mr. Rock. This office was 
at 116 Nassau Street, New York City. 

It is most interesting to contrast the little plant shown in Fig. 33 
with the motion picture development plants of today. 


Mr. Jenkjns: I suggest that Mr. Richardson's alleged facts 
should be substantiated by citations where evidence may be found to 
support his allegations, i.e., public documents, records, publications, 
ex-parte statements, oaths, etc. 

I believe no one denies that my name is associated in some way 
with the period of transition from peep-hole machines to life-size 
picture projection. 

An analysis of motion picture apparatus discloses that the only 
new essential over old apparatus was the adoption of mea7is for 
getting long illumination of the film at the exposure aperture of the 
projecting machine. That was my contribution, and that is why the 
shutters were left off my early machines (Fig. 34), lantern slides of 
some of which were shown us by Mr. Richardson (see Figs. 4 and 5). 

No projection of well-illuminated, life size motion pictures had 
been attained before the time I refer to, and no machine has been 
made since without this feature. This is conceded by the parties 
whose letters were read by Mr. Richardson. And as both Mr. Armat's 
and Mr. Edison's letters say that Edison got his projector from 
Mr. Armat and put his name to it in order to get more money out of 
the public, it would seem to be only a question of evidence of invention 
as between Mr. Armat and myself. 

You doubtless noted yesterday that in Mr. Armat's letter he says 
he changed the name of his projector to the "Edison Projectoscope" 
or "Edison Kinetoscope" (from the original name Phantoscope). 

Now "Phantoscope" is the fanciful name I had given all my 
motion picture apparatus. 

If you will look up the Photographic Times of July 6, 1894, which 
can be consulted in any of the larger public libraries, you will find 
that this name "Phantoscope" was applied to my machines, with 
descriptions and accounts of exhibitions of them, months before I ever 
met Mr. Armat. 


Transactions of S.M.P.E., September 1925 

Many friends saw these exhibitions, and their affidavits and 
testimony can be found in suit Equity No. 5/167, U. S. Circuit Court, 
Southern District of New York. There also can be found the affidavit 
and testimony of the workman who made several of these machines 
for me, including the construction of^the^" 1893-94 Phantoscope,'' 
the construction of which was paid for by J. P. Freeman. 









r -4jiy 


\l I 

Fig. 34. The Jenkins Sole Application which was put in interference with the 
Armat-Jenkins joint application. 

Mr. Armat, after investigating a machine of mine which pro- 
jected motion pictures, believed he saw how he could make some 
money out of it as a promoter, as is explained in the preamble of our 
contract signed March 25, 1895, which reads as follows: 

"This agreement, made and entered into this 25th day of March, 1895, in 
duphcate, by and between C. Francis Jenkins, of Washington, D. C, party of the 
first part: and Thomas Armat, of Washington, D. C, party of the second part, 
witnesseth, that — 

Whereas, the party of the first part has filed application for letters patent 
of the U. S. for a certain invention of his known as the 'Phantoscope', and also 
for letters patent on certain new methods of photography, it is agreed that — 

First : For and in consideration of One Dollar and the immediate construc- 
tion and subsequent public exhibition and proper promotion by the party of the 
second part * * * >> 

Discussion 111 

You notice he admits that the Phantoscope is my invention, and 
he proposes to make, exhibit and properly promote my "Phanto- 

Under this contract, three copies of my 1894 machine were made 
and taken to Atlanta, Georgia, for exhibition at the Cotton States 
Exposition. Mr. Armat called in a reporter to write up the trip, and 
his account appeared in the Baltimore Sun, October 2, 1895. The 
article refers to the machine which would be used, as "the Phanto- 
scope, the invention of a Washington stenographer." 





It will be shown for the First Time at the Atlanta Exposition, Where it 
May Reproduce All the Details of a Mexican Bull-Fight Without Fear of Inter- 
ference by Mr. Ballou- It May Also Figure Largely at the Corbett-Fitzsimmons 
Prize-Fight at Dallas. 

(Special dispatch to the Baltimore Sun) 

Washington, October 2, 1895. 

Mr. Armat was not, until much later, interested in claiming 
that he invented the machine, so he continued to give out news stories, 
even during my absence from Atlanta, about 'The Phantoscope," 
for example, in the Atlanta Journal of October 15, 1895, and October 
21, 1895, in which the exhibition of the machine continues to be 
referred to as the "Phantoscope." 

Soon after Mr. Armat's return to Washington, he took one of 
the machines to New York, and there on the second floor of the 
Postal Telegraph Building, he exhibited it to Edison and his associates 
in December, 1895, as Mr. Armat explains in his testimony in the 
Armat-Latham-Castler suit. 

About the same time I made another copy of the original 1894 
Phantoscope machine and exhibited it before the Franklin Institute, 
Philadelphia. The invention was referred to the Committee on 
Science and the Arts for report. In due course, this committee 
recommended the award of the Elliott Cresson gold medal, their 


Transactions of S.M.P.E., September 1925 

highest honor. This recommendation was published for three months 
in the Journal of the Institute, and Mr. Armat protested the proposed 
honor. His protest was dismissed. I quote from the report. 

''Mr. Armat declined to submit testimony to substantiate his claims to 
inventorship, the protest is made up chiefly of aspersions upon the character of 
Mr. Jenkins, which matters are not relevant to the question. No allusion is 
made in said (Jenkins-Armat) agreement to any inventions made or contem- 
plated by Mr. Armat. An interference was declared in the Patent OflSce to 

Fig. 35. A part of the exhibit of apparatus built and used by Mr. Jenkins in the 
development of motion pictures. 

settle the question of inventorship. After Mr. Jenkins' testimony was given, Mr. 
Armat declined to maintain his claim as inventor by giving testimony before the 
Patent Office, but he, at that stage of the case, bought for a cash consideration, 
all of Mr. Jenkins interests in the Phantoscope, and had Mr. Jenkins withdraw 
his application, which made the way clear for the allowance of the joint patent 
(Jenkins-Armat No. 586,953)." Fig. 2. 

So the Elliott Cresson award was made ; and thirteen years later 
a second, the John Scott Medal was given me, perhaps to confirm 
their earlier judgment. I quote from that award. 

Discussion 113 

"Eighteen years ago the appHcant exhibited a commercial motion picture 
projecting machine which he termed the 'Phantoscope'. This was recognized by 
the Institute and subsequently proved to be the first successful form of projecting 
machine for the production of life-size motion pictures from a narrow strip of 
film containing successive phases of motion." 

After signing a contract with Edison, Armat asked the Court to 
stop me from making, using, selling, or exhibiting my machine, or 

C, Franc is Jenkins, 

Washington ,1) .C . Marofc 15 » 1^23 . ^ 

Dear Mr .Jenkins.* 

Kef erring to the 
attached photograph, I can say that 
T recollect that when you were liv- 
ing at our house in 1892 you had a 
camera of which I helieve this to^he 
a photograph. 1 recognize the shape 
and size of , the wooden box, and also 
the crank pin on the face of the ro- 
tating disc. Mrs .Bush says she re- 
members your giving two little darky 
Isoys a nickie each to turn somersault 
while you photographed them with this 

camera. (PJilf^ f , f%,4. " 

Fig. 36. One of the first cameras built by Jenkins. It has a crank pin for giving 
the film an intermittent movement behind the lens, later called the "Beater 

publishing any description of it. But Judge Hagner dismissed the 
suit in my favor, from which decision I quote. (In Equity No. 17, 
416, D. C. Docket 40). 

"Its statements (Photographic Times filed by plaintiff Armat) would seem 
to be of value to defendant Jenkins, inasmuch as it showed his attention had been 

114 Transactions of S.M.P.E., September 1925 

directed to this subject at a period in advance of any intercourse between Armat 
and himself, and long before the date complainants attach to the alleged in- 
ventions of Thomas Armat. The injunction is denied." 

I might say that all the evidence referred to by me this morning 
and much more has been collected and bound, in three copies, one of 
which can be found on deposit in the Franklin Institute. This 
evidence was gotten together at the request of the National Museum, 
at considerable labor and cost, and delivered to Dr. Charles D. 
Walcott, Director, but later, on inquiry, I was told the evidence 
could not be examined as the museum could not consider controversial 
subjects. May I add that much of the old apparatus I made and 
used in developing motion pictures had been in the National Museum 
for twenty-eight years, unchallenged, and can still be found there on 

As to Edison's invention of anything original connected with 
motion pictures, the United States Supreme Court decided he had 
not invented anything which had not already been disclosed by 
others. The decision appears in U. S. Supreme Court Record Vol. 243, 
U. S. 502, 61- L Ed. 871; Vol. 235, Fed. 398; Vol. 232, Fed. 363; 
Vol. 231, Fed. 701; and many others. 

Quoting from C. C. A. 2nd Ckt. March 10, 1902— Fed. 114, 
page 926, the court said: 

''The photographic reproductions of moving objects, the production from 
the negatives of a series of pictures, representing the successive stages of motion, 
and the presentation of them by an exhibiting apparatus to the eye of the specta- 
tor in such rapid sequence as to blend them together and give the effect of a single 
picture in which the objects are moving, had been accomplished long before Mr. 
Edison entered the field." 


By J. H. Hertner* 

There have been a number of papers presented before the Society 
relative to the direct current motion picture arc and the use of various 
types of motor generator sets for the production of such current. In 
several of these papers the relative advantages of the multiple and 
series systems are compared. A quite complete description of the 
multiple arc and the principal requirements of its successful design 
appeared in one of these papers. A brief outline of the design of the 
series arc machine might likewise be of interest. 

The Usual Design of Shunt Wound Generators 
Beginning with a generator of the usual design, unless some 
method is provided of increasing the magnetic strength of its fields, 
the effect of added ampere load is to cause the voltage produced to 
decrease and in a shunt wound machine this effect is so marked as 
to make the generator almost useless where a uniform voltage pressure 
is desired. A machine of this kind with the brushes set at the neutral 
point even if hghtly loaded will immediately begin to lose voltage 
unless some means of continuous regulation of field strength is 
provided. This is due to several causes. 

First, the losses in the armature and brushes must be subtracted 
from the voltage generated and this will cause a voltage loss propor- 
tionate to the load. Second, the armature, excited, becomes a magnet 
at right angles to the poles ; its effect is to strengthen the trailing pole 
tips and to weaken the leading tips. Owing, however, to the fact that 
the permeability of iron is not constant, the net effect is to weaken 
the resultant field strength which decreases the voltage produced. 
Third, the field winding being now less strongly energized, the poles 
become weaker, producing less excitation so that the total effect is 
cumulative. A point is reached, where, if it is attempted to allow 
more current to flow by lowering the resistance of the load circuit, 
the voltage generated decreases so rapidly that the current remains 
constant over quite a voltage range and finally beyond this point the 
current will actually decrease as its path becomes less and less 

* The Hertner Electric Company, Cleveland, Ohio. 


116 Transactions of S.M.P.E., September 1925 

Under ordinary conditions of design the current will not attain 
the critical point of constancy until the load has reached a value 
which is far in excess of what the machine can safely carry continu- 
ously, Fig. 1, hence means must be adopted to hasten this condition 
in order to have the current remain substantially constant over the 
entire working range of the generator. There are several ways of 
accomplishing this. 

vjOLT AropeRC pewFORcoAfice cvRue. 

OF Type D -75-75' 

BRvSHes se.r on rie\yrRPic 


60 80 lOO 

Constant Current with Reversed Series 
If the load current is carried around the field poles in a direction 
contrary to that of the shunt circuit, a demagnetizing eifect is pro- 
duced that is proportional to the load itself and which is zero at no 
load. This will carry the volt-ampere curve from the postion shown 
in Fig. 1 to that shown in Fig. 2. It may be remarked here that the 
effect of these reversed series turns is naturally but slight near the 
lower parts of the curve where the current is low. 

Constant Current with Armature Reaction 
A second method of control is available. Looking again at Fig. 1 
where, as already explained, the effect of the load circuit is to cause 

Projection Motor Generator Control — Hertner 117 

the armature to become a magnet at right angles with the field, 
suppose the brushes are moved in the direcion of rotation, the mag- 
netism produced by the armature will oppose the field in the same 
measure as the brushes have passed the neutral point and this com- 
ponent is in effect the same as if the load current passed around the 
field poles opposite in direction to that of the shunt, as already 
explained. By proper rocking, the volt ampere curve becomes the 
same as if the demagnetizing effect were produced by the use of the 
series field, and shown in Fig. 2. 

uoLTAnpe«e peRFo«M«ticecuRv/fc 

OF TYP E- P-7S-7 5' 


20 ^ 60 80 100 

Fig. 3 represents the magnetic lines as produced by the shunt 
field and with the brushes in neutral before any current is drawn from 
the generator. The arrow a indicates the direction and magnitude 
of this field. It will be noted that its distribution is substantially 
uniform. Fig. 4 shows the effect of a load in the armature. A cross 
field indicated by h is produced, giving with a resultant c shown, and 
with the distortion shown in Fig. 5. 

[Rocking the brushes as shown in Fig. 6 breaks up the armature 
magneto motive force into two components one of which d opposes 
the shunt magneto motive force a and has the effect of a reversed 
series field producing a resultant e of less magnitude than c already 
shown, and a distortion as pictured in Fig. 7. 


Transactions of S.M.P.E., September 1925 

To run two arcs in series requires about 120 volts and if the 
machine is to operate at 55 to 60 volts and again at 110 to 120 volts, 

SHv/nr F(eLO noc^nAL,wiTH load 


it is evident that on open circuit the voltage must be in the neighbor- 
hood of 200. Such a machine on a single arc at 60 volts is running on 

Projection Motor Generator Control — Herlner 


a very weak field and likely to spark so that it becomes advisable to 
use interpole coils. 

Compound Winding Versus Armature Reaction 
With the compound wound machine the governing action to 
retain constancy of current must come from the series fields and as 



they are located on the poles, the flux throughout the entire magnetic 
circuit must change to comply with the new condition. The flux for 
two arcs or 120 volts is substantially twice what it is on 60 volts. If 
the opposing force is in the armature itself, the field structure does 

f(6. ?- RESULTftnT Of FteLOS WITH 
OP F(G. e. 

not enter into consideration to the same extent as it does with the 
reversed series field since a leakage flux is developed that need not 
travel through the field structure which ordinarily is not laminated 


Transactions of S.M.P.E., September 1925 

and which introduces an element of sluggishness into the action. 
In the case of rapid fluctuations of the arc resistance there must be 
an instantaneous adjustment of magnetic flux and voltage if there 
are to be no current fluctuations. The control effected by means of 
armature reaction appears to have eliminated the current surges 
present in the compound generator on the high intensity arc. 

Behavior of the Arc 
It has been argued against the series generator that it is difficult 
to start the first arc in that it must be touched and pulled quickly. It 
has been found, however, that after a few attempts no difficulty will 
be experienced from this source. A very easy wa}^ of starting the arc 
is to bring the carbons together lightly with the short circuiting switch 
closed, next open the switch, a current will flow which is only a 
fraction of the full load current and a pressure of a few volts will be 
developed. If now the carbons are separated a trifle, the machine 
will build up full voltage and if the carbons are then touched the arc 
will follow without difficulty. The foregoing procedure eliminates the 

Projection Motor Generator Control- — Hertner 


uncertainty of bringing the carbons together for an instant from an 
uncertain distance apart separating them promptly enough so as not 
to demagnetize the generator and only far enough as so to draw, and 
not to extinguish, the arc. 

Starting the second arc on a series generator is, if anj^thing, 
easier than with the multiple machine. If the carbons are touched 
together and the short-circuiting switch opened a short time before 
the arc is drawn, and full load current will pass between the carbons 


im •i^ 


F yiiLignF yb 

Fig. 9. 

with about a 5-volt drop furnishing enough energy to bring them to 
a red heat so that on separating them, the arc will follow quietly 
without the necessity of warming up the tips while the arc is burning. 
The curve of performance of the series arc machine on increasing 
voltage does not follow the curve on decreasing voltage. This, of 
course, is due to the retentivity of the iron. To get the nearest to a 
constant current performance on one and two arcs the descending 
curve or the one of amperes and decreasing voltage should be used 
in which case after the second arc has been struck going back to the 
single arc will cause no change in current value. 

122 Transactions of S.M.P.E., September 1925 

Fig. 8 shows such a close coupled motor generator of this type 
in section. In this unit the motor is below with the generator above, 
all ball bearing mounted. Fig. 9 is the same machine externally. 

The exact handling of either the series or multiple generator is 
sometimes a matter of the personal taste of the projectionist. There 
are those who desire the nearest approach to unvarying current from 
two to one and one to two arcs and who will keep their arc lengths 
adjusted to very close limits. When using a multiple arc machine, 
many prefer a generator somewhat over compounded so that the 
points of single and double arc current are at about the same voltage. 
This, in spite of the fact that on open circuit the voltage will be con- 
siderably lower than on load. It might appear that this would lead 
to some difficulty inasmuch as when the arc length increases the 
current would drop off more rapidly because even on constant arc 
length the voltage drop across an arc is greater as the current de- 
creases. With a lower voltage generated on light load, this effect 
would be more pronounced. But it must be remembered that the 
ballast drop decreases at the same time in proportion to the current 
decrease and that the performance curve is convex so that the effect 
of drop in generated voltage is slight until a point is reached where 
the current is considerably below normal so that the open circuit 
voltage can be somewhat lower than the full load voltage without 
any appreciably undesirable effect. The wide use of automatic control 
has also largely eliminated the possibility of a loss of the arc on 
account of too infrequent adjustments. 


Mr. Kunzmann: Our laboratory tests are mostly conducted on 
110-volt D.C. circuits, and we have found that the most satisfactory 
operation with low intensity carbon arcs starts at 52 volts with 
30 amperes and with every 10 amperes increase we increase the volt- 
age by 2 at the arc. Do you find this to apply also? 

Mr. Hertnee: On heavier currents you want higher voltage 
across the carbons for the best results. On the reflector type arc we 
can run at slightly lower voltage than on the higher amperes. You 
can run from 50 to 55 volts on the reflector arc with 30 amperes and 
on 125 amperes about 65 volts. 

Mr. Kunzmann: On the reflector arc operation, we find when 
you get away from 55 volts at the arc, you get unsatisfactory arc 

Discussion 123 

operation, with the result that a quarter inch arc length cannot be 
maintained; hence an unstable arc. 

Mr. Richardson: I have observed that the necessary voltage 
of the arc within rather narrow limits changes with the composition 
of the carbon. Does the arc stream or the gas stream vary with the 
composition of the carbon? 

Mr. Kunzmann: It depends on the chemical used in the core 
of the carbon. 

Mr. Richardson: I have discovered in projecting pictures that 
there was a difference in the quality of the light from different 
generators. Did you ever hear of such a thing, and if you did, do you 
know the reason for it? 

Mr. Hertner: Were those experiments made with different 
carbons on the same generator? All generators give you a constant 
current. If you take a curve of the current stream you would not 
find any appreciable variation due to the generator itself, so I cannot 
understand how different generators could be responsible for the 

Mr. Ruben: I can substantiate Mr. Richardson's statements. 
I also have projected for many years and have always thought that 
50 or 75 amperes was 50 or 75 amperes, but I have found with the 
same current values, carbons, projectors, and projectionist, the same 
room, screen, and lenses, there was a variation in the quality of the 
light with different motor generator sets. Some will produce a blue 
light and some a yellow light. Salesmen of different generator sets 
have used this as a sales argument. One claims blue light is better 
and the other claims that yellow Hght is better. 

Mr. Briefer: In connection with that point, I should like to 
ask if the quality of the light continued with the same conditions 
or if it varied as the carbons were used. 

Mr. Palmer: I have observed the same thing under different 
conditions. The arc lights burning in a studio from a studio generator 
of small size give a different kind of hght from that which they emit 
when used on a large central station system, you get more light than 
if a small generator were used, which I attributed to the fact that 
on a large system you are operating off a system with machines run- 
ning in parallel and there is no hum in the arc due to commutation 
of the small machine. 

Mr. Kunzmann : I should like to ask if the observations which 
Mr. Richardson and Mr. Ruben speak of were made on a white 
screen or with film projected on the screen. 

124 Transactions of S.M.P.E., September 1925 

Mr. Richardson: The difference was even apparent at the spot. 

Mr. Kunzmann: You can effect a considerable change in the 
condensing system; also a noticeable change in color and candle- 
power due to condenser discoloration. 

Mr. Richardson: We had two generators. They were the same 
size and make, and there was a decided and pronounced difference 
when we had to change from one to the other. After that it attracted 
my attention so much that I talked with other men and made experi- 
ments in other places and found it was true. 

Mr. Hertner: I was going to suggest that it would have been 
an excellent chance for Mr. Richardson to change carbons, and I 
think this would have solved the problem. 

Mr. Richardson: That was done a couple of times. We changed 
in the middle of a train and the quality of the light was entirely 

Mr. Hertner: Did you carry the same individual carbons 
over to the other machine? 

Mr. Richardson: It was the same machine, nothing was 

Mr. Powrie: I have recently discovered some local variations 
in the carbons of a projection lamp we have been using. There was 
a change in the character of the carbon that produced quite a marked 
variation in the quality of the light. I think local variations in the 
carbon has much to do with the fluctuation of the light. 

Mr. Ruben: I want it more thoroughly understood. A certain 
theatre has a generator manufactured by Mr. Hertner, and one of 
another make. Whenever Mr. Hertner's is used, the light is more 
brilliant. The amperage is the same and the conditions are the same, 
but there is no question Mr. Hertner's gives more brilliance, it is 
whiter and has more life. 

Mr. Kunzmann: The mirror arc carbons referred to have a 
neutral core, but with high intensity carbons, the hght emitted 
comes from the gas ball from the core. Unless there is some chemical 
spilled over a neutral cored shell the effect referred to in my opinion 
would not be noticeable providing all tests were made under the 
same conditions. 

Mr. Kroesen : I would be interested in knowing if a comparison 
has been made between the mercury arc rectifier and other sources 
of current supply, and what the operating results at the carbon 
electrodes are. I am under the impression that a rectifier is the more 
desirable insofar as the quality of light on the screen is concerned. 

Discussion 125 

Dk. Gage: In answer to Mr. Kroesen's inquiry, quite a while 
ago we made some tests that were published in the Electrical World 
comparing the candle power of the same amperage using the rectifier 
and using direct current. We found apparently a very slightly less 
candle power as indicated by a direct current meter when we used 
the mercury arc rectifier. The question that Mr. Palmer brought up 
may be the clue to a proper method of inquiry. We have a series of 
machines supplying an arc with the same number of amperes, as 
indicated by a direct current meter, and if there is a difference in 
light, it would be attributable to an alternating current superposed 
on the direct current, which is indicated by a commutator hum. 
It would be interesting to get some data on this disputed point. 

Mr. Richardson: How can you superpose direct current on 
alternating current with a motor generator set? 

Dr. Gage: I mean commutator hum. 

Mr. Richardson: You mean the variation in the rectification 
of the current. 

Mr. Hertner: In motor generators, there is no definable 
difference in the direct current. I don't think the variation would 
be sufficient to make a difference, but on a mercury arc rectifier, 
there would be an appreciable difference depending on how you 
measure the current. If you get an average in amperes with one 
and a square root mean on the other, it might show up a difference. 

Mr. Ruben: I have noticed the effect is more pronounced, 
that is, the quality is better with constant current type generators 
than with the constant voltage type, which gives a yellower light. 
It may be that the open circuit voltage on a constant current type 
is much higher with the other. For probably the same reason I have 
noticed in an arc produced with a commercial direct current at 220 
volts stepped down through a rheostat the light is much better and 
stronger than from a 110-volt circuit, and I thought that possibly 
it is so much brighter due to the higher original voltage impressed. 

Mr. Hertner: That suggests a possible explanation. When 
you run a multiple machine, unless you keep the arc length about 
right, you will lose your current and the projectionist will watch 
this and automatically set his arc shorter. On the series machine, 
this does not hold true, as on most of these machines it will increase. 
This means that it is quite possible that the arc is allowed to run 
long, which produces whiter light. 

Mr. Kunzmann: I also have observed this. 

126 Transactions of S.M.P.E., September 1925 

Mr. Manheimer: I know there is such a thing as the counter 
e.m.f. of an arc and perhaps this would explain the difficulty. 

Mr. Kunzmann: I might add that I have been present at light 
demonstrations where twenty or thirty people have been present 
for determining an increase or decrease of light, and in the majority 
of cases, 15 to 20 per cent differences of light could not be detected 
with the unaided eye by those present. 

Mr. Richardson: That is true, but you will admit that while 
the eye is not sensitive to an increase or a decrease, it is sensitive to 
differences in quality. 


Gentlemen : 

Your Committee has been diligently corresponding regarding 
the various problems assigned to it at the last convention. We also 
spent one day in New York, discussing the work, and have had a 
meeting here at Schenectady, the results of which we offer for your 


You will recall that at Chicago, you gave final acceptance to a 
standard observation port 16 in. square, with its center located 
5 ft. 3 in. above the floor, based on a zero projection angle. The center 
of the port to be lowered one inch for each degree drop in angle of 

You also accepted, after the required six months' consideration, 
a standard maximum cutting width for standard positive film of 
35 mm. or 1.378 in. 

Standards Up For Final Adoption 

The following matters were thproughly discussed and accepted 
at the Chicago convention. They have now stood unchallenged for 
the required six months' period. We, therefore, recommend that you 
give them your final approval at this time. 

The question of the form of perforation for 35 mm. film was 
again discussed at Chicago. It was stated that several different forms 
would be tried out during the coming year; therefore, the matter of 
standardizing should be held in abeyance pending the results of such 
tests. Your Committee has not secured any further data in this 
connection. If anyone has any authentic information on these new 
forms, we hope he will present it now. 

Your Committee has been in touch with the English, French 
and German Sooieties, and are advised by Mr. L. Lobel of the French 
organization that they have agreed to the same form and dimensions 
of perforation for positive film which we have recommended, i.e., a 
rectangular hole 1.98 x 2.79 mm. with rounded corners. (Fig. A, p. 
238, No. 18 Transactions). There seems, however, to be some feel- 
ing on the part of Pathe that his perforation, 3 mm. long x 2 mm. high, 


128 Transactions of S.M.P.E., September 1925 

having straight top and bottom edges, but ends formed by the arc of 
a qircle, and joined to the top and bottom by rounded corners, is 
better, and this may be standardized also. For negative film, they 
also have accepted our practice of perforations 1.85 x 2.79 mm. with 
rounded ends. (Fig. A, p. 238, No. 18 Transactions). 

As the use and value of other forms of perforations than the 
rectangular with rounded corners for 35 mm. positive film, proposed 
at the Roscoe meeting a year ago, (as shown in Fig. A, p. 238, No. 18 
Transactions), seems doubtful, and as the foreign practice seems 
to be going also to the same perforation, your Committee recommends 
that you now accept for final standardization this form of perforation. 

At our last convention, your Standards Committee stuck to 
their guns and again recommended the same dimensions for camera 
and printer apertures as proposed at Roscoe a year ago, i.e., that 
the black border is desirable, and to obtain it we recommended the 
following aperture sizes: 

Camera: .700 in. hi,gh x .925 in. wide; .035 in. radius corners 
Printer: .757 in. high x 1.000 in. wide; 3/64 in. radius corners 
Projector: (already standardized as .725 in. high x .950 in. 
wide; square corners.) 

The camera aperture corners may be either square or rounded, 
but the projector aperture corners must be square. 

This recommendation has now stood for the required six months, 
and we recommend that you give it your final approval at this time. 

At our last convention, we gave you a demonstration of pro- 
jector speeds, and recommended as standard practice 80 ft. per 
minute, with a maximum of 85 ft. ; and a minimum of 75. ft. We now 
suggest that you give th^is your final approval. 

At the Chicago convention, the Committee's recommendation 
that we standardize 2-25/32 in. as the external diameter of the barrels 
of No. 2 size projection lenses was accepted. We now suggest that 
you give this your final approval. 


President Jones: I will call for discussion on this section of 
the report. 

Dr. Mees: In view of the fact that at the beginning of July the 
International Congress of Photography will deal with these matters 
in their Cinematograph section, it might be well for the Society to 

Discussion 129 

withhold its decision until the report is received from the Inter- 
national Congress. If we settle the matter now, we should have 
some difficulty in going back on our decision, if, after the Inter- 
national Congress, it seems desirable to change it. 

Me. Porter: I will read a telegram on that matter which I have 
just received: 

London, England, May 19, 1925: British Standards Committee plead 
perforation shape remain. Congratulate your society on adoption width films 
and aperture sizes. Agree number two lens barrel. Suggest number one size 
2 — 1/32. British delegates to Paris will be pleased to meet your delegates in 
London prior to Congress. Brooke Wilkinson. 

Dr. Story: The suggestion has been made in one of the later 
paragraphs of the tentative report now submitted that as some of 
our members are going to Paris, that they would be able to represent 
us very easily there, and I think it would be courteous for us to leave 
as many of these matters open as we can until afrer that international 

Mr. Davidson: To avoid adopting a standard we may not be 
able to keep, I move that action on that part of the report referring 
to standards down to ''Nomenclature" be postponed until the 
autumn meeting. 

Motion seconded and duly passed. 

Mr. Porter: We are now down to "Nomenclature." The 
following nomenclature was adopted at Chicago and is before you 
now for further disposition. 

Retake: The action of photographing scenes, or the negative 
resultant therefrom, when the negative or negatives previously 
obtained are unsatisfactory. 

Scene: A division of the story showing continuous action in the 
same locale or set, and taken from the same point of view. 

Film Gate: A movable element which, when in operating position 
holds the film in register against the aperture plate. 

Cooling Plate : A shield or baffle composed of one or more plates 
mounted between the fight source and the mechanism, and usually 
attached to the latter but spaced therefrom, to prevent overheating 
the mechanism. 

Dr. Mees: I move that it be adopted. Motion seconded. 

Dr. Story: I have understood from men in the laboratories 
that the definition in the Report of "scene" is incorrect. They say 
a scene is not necessarily taken from the same point of view, and in 

130 Transactions of S.M.P.E., September 1925 

many of the later productions the camera has been moved around 
during the action without the scene being considered changed. 

Mr. Renwick: This committee had such great difficulty in 
formulating a definition for scene that it was thrown open to the 
Society, and we are indebted for this one to Mr. Chanier. To meet 
Dr. Story's objection, I suggest that it be changed now to read "but 
usually taken from the same point of view." 

Mr. Crabtree: I move that the words in question be deleted. 

Dr. Mees: I move that the definition of "scene" be adopted 
subject to final adoption six months hence with the word "usually" 
inserted in it. Motion seconded. 

Dr. Story: I believe that "usually" will never make an un- 
satisfactory definition a satisfactory one. A definition should be suf- 
ficiently general to cover the term wherever it is used. I do not think 
the definition which sometimes applies wiU do. 

Mr. Davidson: I think "usually" is often used in definitions. 
I do not see why the phrase at the end could not be removed al- 
together as a matter of fact, but I don't see any objection to the word 

Dr. Story: There are several other faults with that definition 
as I see it, for instance, "continuous action." It may be intermittent 
action ; it is not necessarily continuous. May I say also that I do not 
beheve we can be too careful about the exact wording of the definition 
in our nomenclature any more than we can be too particular of the 
numerical value of our standards. These are the things that the 
industry looks to our Society to establish, and we should be sure 
that they get the best we can give them. 

Dr. Gage: It seems to me that the real meaning of a scene 
might be expressed as "a division of the story showing apparently 
continuous action." If the location of the action is continuously 
moved, you can move the camera to keep track of it, but if the scene 
is changed, everything is changed. In a single scene, the camera 
may have been stopped, but a section of the story on one strip of 
film shows uninterrupted action as it is supposed to have taken place. 

Dr. Story : I should like to que^ion the definition of the word 
"retake." Is not the re-photographing of a scene a retake unless the 
previous negatives were unsatisfactory? 

Mr. Renwick: We had great diversity of opinion on this term 
at previous meetings, and speaking for myself I can only say that it 
was news to me that this was the general definition of "retake," but 

Discussion 131 

I think it expresses the views of its users and is, therefore, in accord- 
ance with the Society's intentions. 

Mr. Fritts : I move that an amendment be made to the motion, 
namely, that we adopt the paragraph on "Nomenclature" with the 
exception of the definition of "scene." 

Amendment seconded and passed. 

Mr. Porter: Since coming to the meeting, the question has 
been raised about the new type of lamp coming into use known as 
"low intensity arc," "reflector arc," etc., as to how it should be 
defined to distinguish it from the other types in common use, and 
your Committee suggests this definition as written on the blackboard. 

"Reflector Arc Lamp: In a motion picture projector an arc 
light source in combination with a reflector to project the light beam 
through the aperture." 

Mr. Kunzmann: I am going to offer an alternative: The re- 
flector arc lamp in a motion picture projector is a carbon light source 
operating in a right angle or horizontal position in combination with 
the mirror reflector to project the light beam through the projector 

Mr. Porter : In some cases condenser lenses are used in addition 
to the mirror, and while the present practice is right angled, I don't 
think it will necessarily remain so. 

Dr. Mees: I think that definition misses the essential point of 
the reflector com^pared with the ordinary arc, that the crater of the 
carbon is turned away from the aperture; in an ordinary arc, the 
crater of the carbon is turned towards the condenser. 

Mr. Porter: In most cases that is true, but how about where 
they use the prism machines with a right angle turn of the beam of 

Dr. Mees: It is turned away from the screen, that is, towards 
the mirror. 

Mr. Kunzmann : The prism reflected arc is not a reflector, and 
I think that some mention should be made in defining this new unit 
of the position of the arc in relation to the reflector. 

Dr. Story: Is not the essential difference between the reflector 
arc and the ordinary arc, however, that the light is concentrated on 
the aperture in one case by a curved mirror with or without a lens 
and in the other case by means of a lens alone? 

Dr. Gage: I am afraid I must question the whole definition. 
You cannot have a reflector arc lamp; there isn't any such thing. 

132 Transactions of S.M.P.E., September 1925 

Suppose you start with a right angle or some other angle and face it 
toward the refractive condenser, would you call this a refractor arc 
lamp? And, turning the thing around and facing it toward the 
reflector would you call it a reflector arc lamp? 

Me. Davidson : Cannot a reflector be used on a stereopticon as 
as well as on a motion picture projector? Should we narrow the 
definition to apply merely to motion picture projection? 

. Dr. Mees : I move that this be referred back to the Committee. 
Motion duly carried. 

Mr. Porter: Your committee would greatly appreciate it if 
you would write them your suggestions. 

We are now down to the part of the report referring to new 

At the time we adopted the dimensions for 35 mm. film, no tolerances 
were specified. The English object to the increased height of the Eastman per- 
foration on the ground that if the sprocket wheels of the various machines were 
first standardized, the extra height would be unnecessary. The French and 
Germans propose tolerances which would probably be applicable here. They are 
as follows: 





+ .0127 mm. 

± ? 

± .01 mm. 


± .0127 mm. 


+ .01 mm. 

Longitudinal Pitch 

+0, -.012 mm. 

.01 mm. 

+ .005 mm. 

Transverse Pitch 

± .025 mm. (?) 

.05 mm. 

+ .01 mm. 

Also, that forty perforations should occupy 190 mm. +.2 mm. (German). 

The problem, therefore, before us is whether or not it is desirable to add 
tolerances to the dimensions we have already standardized. If it is, it would 
seem desirable to conform to European practice and adopt the tolerances given 

Mr. Renwick: I think this question of tolerances also might 
well be left over to be considered at the next meeting as the question 
of perforations is to be dealt with at the congress in Paris. I make a 
motion that the matter be left until we have the International report 
in our hands. Motion seconded. 

Dr. Mees: I should like to know the opinion of the Society 
with regard to the standardization of sprockets. The English and 
French have laid great stress on standardizing the sprockets first. 
I imagine this Society is in accord with that, but I should like to 
know the view of the Committee. 

Mr. Porter: Your Committee tried to get data together on 
this subject; we hoped to have a compilation of the design of sprock- 

Dismission 133 

ets here and abroad, but we have not had time to do it. Mr. Jones 
says by the time of the fall meeting, he will have these data together. 

Dr. Mees: What action am I to take should I find myself 
confronted with a motion to standardize sprockets? Shall I consult 
Mr. Jones and take his advice? 

Mr. Porter: I think that will be very satisfactory to the 
Committee. How does the membership feel about it? 

Dr. Mees: Are you voting against a binding requirement by 
the foreign committee that sprockets be standardized? 

Mr. John Jones : I should vote in favor of the standardization 
of sprockets although the actual specifications would be matter for 

Mr. Davidson: Would you agree to tolerances? 

Mr. John Jones: Yes. 

President Jones: The motion before the house is that action 
on this particular section be delayed. 

Motion duly carried. 

Mr. Porter: "Europeans are discussing shrinkage in connection 
with film measurement. They propose to make measurements after 
the film has been developed and dried, so that it will be in condition 
to use on the projector, rather than measuring the freshly perforated 
film as the Society of Motion Picture Engineers decided to do after 
lengthy discussion of this question. The French propose to let each 
manufacturer determine the shrinkage of his own film after develop- 
ment and drying. It is proposed to standardize conditions of drying 
for laboratory test of film, to determine its coefficient of shrinkage; 
drying, for example, to be for a determined length of time at a fixed 
temperature, and a definite hygrometric condition. The French 
discriminate between longitudinal pitch of positive film and negative 
film, and quite properly make the pitch of the negative film some- 
what greater than that of the positive film to allow for the shrinkage 
which occurs during developing, washing, and drying, so that after 
these operations, it will have, as nearly as possible, the same dimen- 
sions as freshly perforated positive film. Full discussion of the 
European proposals is invited." 

Mr. Kelley: Some time ago, the Department of Standards at 
Washington undertook to measure the expansion and contraction of 
film for patent purposes, and I think I could submit their report to 
your Committee for consideration because they found no definite 
change they could lay their fingers on. I think you must arrive at a 
standard by some different means. 

134 Transactions of S.M.P.E., September 1925 

Dr. Mees: I think the French are too optimistic in relying on 
the manufacturer to determine the coefficient of shrinkage of his 
material. The shrinkage of motion picture film is very difficult to 
standardize, and I think the Society has been wise in standardizing 
on film as it is manufactured. What happens in processing is in the 
hands of the physical chemists. 

Mr. Renwick: I agree with Dr. Mees, but there is this very 
important point, that we have not distinguished between the pitch 
of positive motion picture film and of negative motion picture film. 
In Europe, they think they should be different so that positive film 
may match developed, fixed, and washed negative film. 

Mr. John Jones: In that connection, in matching up the 
negative film with the raw positive, there is not enough difference 
due to shrinkage to prevent the claws from pulling down the negative 
to meet the positive. The shrinkage is so slight that it does not 
warrant the pitch of the negative being more than that of the positive. 
We do not notice any difference in this. Even a shrinkage of as much 
as 3 per cent does not make any difference. 

Mr. Kelley: It is my impression that we should use the same 
standard for both negative and positive. The differences are so 
slight that you can depend on the machine. The negative will vary 
in the same roll according to how it is dried. 

Dr. Mees : It has been our experience in the humid atmosphere 
of England that the laboratories tm-n out film with a longer pitch 
than it had original^. The drying conditions do not dry the film 
down as far as it was dried by the maker; this does not apply here, 
where there is uniformly a contraction of fihii, but I think a difference 
in pitch would not be advantageous on the whole though it is theoret 
ically an obvious thing to do. 

President Jones: Does the Society wish to go on record in any 
particular respect with regard to this? There is no motion before the 
house, and I suggest that we proceed. 

Mr. Porter: "Your Committee has followed your instructions 
and investigated the question of camera speed. From the data we 
have been able to collect, it seems apparent that the best camera 
men try to stick pretty close to a speed of 60 ft. per minute. In this 
connection the Committee was greatly aided by Mr. Earl Denison, 
who submitted stop watch tests on a number of well known camera 
men, shooting various types of pictures. The matter was taken up 
with the American Society of Cinematographers, who strongly 
recommend 60 ft. per minute. 

Discussion 135 

"From the data available, j^our Committee recommends (for 
the first time) as standard practice, a camera taking speed of 60 ft. 
per minute, with a minimum of 55 ft.; and a maximum of 65 ft. 
when normal action is desired in connection with the Society of 
Motion Picture Engineers' recommended practice of 80 ft. per 
minute projection speed." 

De. Story: We have tentatively adopted a projection speed of 
80 ft. a minute with a taking speed of 60 ft. a minute; I should like 
to know why we propose a taking speed which will give a distortion 
in action. 

Dr. Mees : I agree with Dr. Story in. this. In working out the 
Cine Kodak, we adopted a speed for taking and projecting of 60 ft. 
a minute, and I have no doubt that it is an advantage for all regular 
practice. ^Yhile I know that the theatres will project at 80 ft. or 
even 100 ft. a minute and that the cameramen will take at 60 ft. a 
minute, I think the Society should not endorse this practice. 

Mr. Kelley: This is a good recommendation. My experience 
is that a taking speed of 60 ft. a minute and a projecting speed of 
80 ft. a minute do not produce an abnormal result. The cameramen 
are not machines and from watching many at work, I am of the 
opinion that most turn their cranks at a speed under 60 ft. a minute. 
We set up a camera having a meter attached giving the rates in 
pictures per second for the chief cameraman on the Fairbanks lot 
and had him operate the camera in making tests shots. It was of 
great interest to us to note that the meter held steady at twelve 
pictures per second (45 ft. per minute) on all takes. Standards will 
mean nothing unless cameras are fitted with tachometers. 

Dr. Story: I would like to call your attention once more to the 
general matter of tolerences. As this reads, the standard taking 
speed is 60 ft. a minute with a minimum of 55 ft. As a matter of fact, 
the tolerance for normal action is zero; by no vote of this Society can 
it be made 5 in. more or less. In standards, there are no tolerances. 
They belong to recommended practice. 

Mr. Egeler: May I ask whether this standard of 80 ft. for 
projection speed has been adopted as a final recommendation? I do 
not see how you can tie 60 ft. a minute taking speed and 80 ft. a 
minute projection speed together, and call them normal. 

President Jones : Action has been suspended until the autumn 
meeting; it has not been finally adopted. 

136 Transactions of S.M.P.E., September 1925 

Mk. Crabteee: Will not the taking and projection speeds 
depend on the "pep" of the actors? I have read of cases where the 
actors have been instructed to act more slowly or faster than normal 
so that this factor would certainly enter into the question. 

With regard to the relative speeds or taking and projection, I 
do not think it is necessary that they should be equal because a 
projection speed of 60 ft. a minute certainly shows lag. We have 
decided unanimously that 80 ft. a minute gives the correct psycholog- 
ical effect when the picture is taken at 60 ft. a minute. 

Mr. Renwick: I wish to say something about the history of 
these recommendations. It is obvious that the members of this 
Committee are neither cameramen nor projectionists, and we have 
been guided by the best information we could get. In Chicago, a 
good demonstration was given and it was the opinion of those present 
that, with the present high intensity light sources, any speed less 
than 75 ft. per minute showed flicker and was undesirable, and on that 
ground 80 was thought very good. The pictures projected at the 
Chicago convention had been taken at the normal speed of 60 ft. a 
minute, and the action by all those present was considered normal 
at the projection speed of 80 ft., so we get this correlation between 
60 ft. and 80 ft. Apparently the mind is not satisfied when the pro- 
jection speed is exactly the same as the taking speed. That is the 
origin of these recommendations, and we are endeavoring to satisfy 
the feeling of the Society. 

Dr. Mees: I agree with Mr. Renwick that most of the pro- 
jectors running below 80 ft. a minute are not satisfactory and give 
flicker, and that is what has settled high speed projection first of all; 
this means that the pull downs are designed wrong or they would not 
give flicker. The Society now proposes standards with its authority 
behind them founded on this error and this is justified by the state- 
ment that the eye cannot pick up the error when made. 

Mr. Porter: Here is a letter from the Society of Cinemato- 
graphers which I would like to read to you. 

Discussion 137 


1219 Guaranty Bldg. 
Holywood, California 

April 28, 1925 
Re Camera Speeds 

Society of Motion Picture Engineers, 
Harrison, N. J. 

Attention Mr. L. C. Porter 

Replying to yours of March 30 and April 15, respectively, regarding our 
opinion as to the correct camera speeds, we wish to state that this matter has 
been discussed from time to time among our members and it is the consensus of 
opinion of our Society that the correct camera speed is sixteen pictures per second 
or sixty feet per minute. This speed has been used for years }:)y practically all 
members of the profession, slower speeds only being resorted to to secure certain 
comedy and dramatic effects. Over-speeding has only been used where certain 
directors have attempted to combat the excessive projection speeds which ex- 
hibitors have adopted to "turn over their audiences" in the shortest possible 
time. We are opposed to any taking speed in excess of 60 feet per minute for the 
following reasons: 

1. Sixty feet per minute is sufficiently fast enough to produce smooth 
action under normal conditions. 

2. Faster taking speeds than 60 feet per minute require that more light 
be used on sets, thereby increasing eye strain of actors. The use of electrical 
equipment, electricians and electrical energy increases cost of production, to 
say nothing of the disadvantages to the cinematographer in securing balanced 
lighting, it being a known fact that better Ughting effects are obtained where it 
is possible to use a minimum of light. 

3. Faster speeds than 60 feet per minute require the use of additional 
negative and positive footage, thereby increasing the cost of raw stock as well 
as the added expense of laboratory work, longer titles, etc. 

4. In recent years, the leading optical manufacturers have improved 
their products, whereby we have obtained lenses with greater speed. These 
improved lenses make it possible to use less light and secure very pleasing effects. 
However, if we are compelled to increase our taking speed we have the equivalent 
of the old methods — 60 feet per minute with the f/3.5 lenses. 

We are glad that you have adopted 80 feet per minute as a standard 
projecting speed, and trust that you will be able to secure the adoption of this 
speed by the exhibitors, it having been our experience that productions photo- 
graphed at 60 feet per minute can be projected at 80 per minute with satisfactory 

We would suggest that your committee adopt some standard for "pro- 
jection lights"; that is, an "arc intensity" of so many amperes for a given screen 
area and length of throw. Of course, we realize the different theaters require 
special equipment, but certainly something can be done to obviate the necessity 
of making special prints for exhibition in the key cities as, we understand, is the 
case of some productions. 

138 Transactions of S.M.P.E., September 1925 

We hope that we have answered your questions, and if v\q can render 
further assistance along these Hnes, please call on us. 

John W. Boyle, Secretary 

President Jones: '\^liat are your wishes with regard to this 
recommendation? We should have some definite action if only to 
instruct the committee. 

Dr. Story: I should like to see it referred back to the Committee 
Motion seconded. Duly carried. 

Mr. Porter: "We have reviewed the data presented at Chicago 
in connection with the outside barrel diameter of No 1 size projection 
lenses, and have been in further correspondence with the manufac- 
turers on this subject. Your Committee now feels that there would be 
a distinct advantage in the increased illumination possible \^ith the 
larger diameter barrel now in common use with Bausch and Lomb 
lenses, giving a full free lens opening of 43 1/2 mm. as against 39 
and 40 of other makes of lenses. We, therefore, (for the first time) 
definitely recommend standardizing on an external diameter of 2- 
1/32 in. for the No. 1 size lens barrels." 

In that connection I have a cable from England which saj^s 
"agree No. 2 lens barrel. Suggest No. 1 size 2-1/32." In other words, 
they agree with our recommendation. 

Dr. Story: If my memory does not play me false, when we 
adopted the standard diameter for the No. 2 lens, it was larger than 
the figures used on the Bausch and Lomb No. 2. That size was 
adopted in order to include the largest of the No. 2 projection lenses, 
and the Bausch and Lomb representatives agreed to increase their 
flange dimensions to fit that standard. At the same time, the other 
manufacturers agreed to bring their dimensions of the No. 1 lens up 
to fit the then new Bausch and Lomb No. 1. It was a question of one 
company modifying its dimensions on one lens and the other company 
modifying its dimensions on the other, so it would seem that no 
great injustice has been done to anyone. 

Mr. Reich: I believe that Dr. Story's memory is incorrect in 
that we agreed to change the size of our No. 1 lenses. We introduced 
the No. 1 size lens and established the standard of 1-15/16 diameter 
in 1908 and this size was not made by others until several years 
later, during which time many thousands of our lenses were sold. 
This was at least eight or nine years before Bausch and Lomb Optical 
Conipany made their Series 1 lenses. 

Discussion - 139 

President Joxes: Air. Porter has called to my attention the 
No. 19 Trajs^sactions, pp. 63-66, in which the entire matter is very 
clearly stated, and there are two letters given there which will take 
some time to read here, but anyone can learn the full status by 
reference to the correspondence on this subject. What are your 
\sishes with regard to this section? 

Motion made and seconded that the recommendation be adopted. 

Mr. Reich: Before the motion is adopted, I wonder how many 
have read the letters and know the differences in the standards. 
The amount of light transmitted through the Xo. 1 is that coming 
through the full aperture. ^Tien you increase a lens opening from 
4 to 4-1/2 or 5 thousandths, the ratio of aperture is changing, and 
the slight difference in this diameter does not enter into the amount 
of light transmitted. 

Dr. Story: I should like to ask Air. Reic-h whether the No. 2 
standard as adopted is that of the Gundlach Alanhattan Lens 

Mr. Reich: It is. 

President Jones: In case you consider it desirable. Air. Porter 
will be glad to read the correspondence. Are you ready for the 
question? Alotion duly carried. 

AIr. Porteb: ''The only information we have been able to 
coUect regarding film splices is that furnished by Air. J. H. AIcNabb 
of the BeU and Howell Company. Air. AIcNabb presents the follow- 
ing as found by them to be best practice. (See figure given in report). 
It seems to the Committee that this might be offered as recommended 
practice rather than as dimensional standard. Therefore, to place 
the matter definitely before you, we recommend (for the first time) 
the dimensions of splice shown in the figure as Society of Alotion 
Picture Engineers' recommended practice." 

Since that time I have recieved a telegram from Air. Denison 
which reads as follows : 

"Your letter dated Alay 20 regarding film splices just received. 
Too late now to do anything for this meeting. At present time I am 
making further research on the question of film splices and can 
assure you that I wiU have very interesting and complete paper 
together with slides for fall convention." 

Mr. Crabtree : I think Air. Jones has data with regard to the 
wearing quality of film with splices of varying width. 


140 Tramadions of S.M.P.E., September 1925 

Me. John Jones: The life of a splice depends on how the splice 
is made. I think this is another matter which might be referred back 
to the committee until the fall meeting. 

Motion carried. 

Mr. Porter: "The question of standardizing film reel cores 
has been studied. Mr. J. G. Jones took this matter up with the 
various camera manufacturers for the committee but found so httle 
interest in the subject that we do not feel that we as yet have suf- 
ficient data to make a definite recommendation. 

Your committee has also studied the European recommendations 
regarding the design of sprockets. Mr. J. G. Jones has prepared a 
review for you which, unfortunately, was not completed in time for 
printing in the advance copies of our report." 

I will ask Mr. Jones to read letters received from four manu- 
facturers at this time. 


109 N. Dearborn St. 
Chicago, 111. 

April 9, 1925 
Mr. J. G. Jones, 
Rochester, N. Y. 
Dear Sir: 

I have your letter of the seventh and will say with the Vox Popper in the 
Daily Press that something should be done about it. 

We who sell motion picture cameras and have sold them for so many years 

always have considerable trouble vdth different new standards of magazine cores. 

Just two years ago when an acquaintance of the "WTiter was chief of the 

Bureau of Standardization of Manufacture under Secretarj^ Hoover, the writer 

continually brought up the matter of magazine cores and lens flanges. 

There is no more reason for the manufacturer to make a flange different 
for the same size of lens than there is to make plate holders different. All sizes 
should fit the same size product. 

Bell and Howell have of course adopted a certain standard for the large 
size magazines which is practical whereas other manufacturers have been using 
the inch standard w^hich seems to be the most practical. 

I certainly for one am heartily in favor of this reform and I am sure it will 
be welcomed in general by manufacturers and consumers so here is more power 
to you in aiding in this reform. 
I remain 

Very truly yours, 

Bass Camera Company 
By Charles Bass 

Discussion 141 


1801 Larchmont Ave, 
Chicago, 111. 

April 9, 1925 
Mr. John G. Jones 
Rochester, N. Y. 
Dear Mr. Jones: 

We are in receipt of your letter of April 7 relative to the proposed standard- 
ization of the camera core of motion picture cameras. 

The question of establishing a standard outer diameter for standard film 
spools is now about seven years old and the Society doesn't seem to be getting 
anywhere with it. Several years ago, the Eastman Company for a short while 
suppHed negative film on spools considerably larger than the present 31/32 in. 
diameter spool. For reasons designated in our letter of October 8, 1921, addressed 
to the Standardization Committee of the Society of Motion Picture Engineers we 
believe the size of these spools should be at least 1-1/2 in. to 1-29/32 in. and for the 
same reasons advanced we would be opposed to the 1 in. core or one of 31/32 in. 

Very truly yours. 
Bell and Howell Company 
By J. K.McNahh, President 


5025 Santa Monica Boulevard 

Los Angeles, Calif. 

May 6, 1925 
Mr. John G. Jones 
Rochester, N. Y. 
Dear Mr. Jones: 

We have your letter of the 17th ult. in regard to standardizing camera 

If you will please refer to the letter by our Mr. G. A. Mitchell to the 
Chicago convention and dated September 25, 1924, which was pubhshed in the 
Transactions of that meeting of the S.M.P.E., you will have our thought in 
this matter. 

You will note that we have adopted a spool measuring 15/16 in. in diameter 
and our experience demonstrates that this functions extremely well both from a 
mechanical point and also from an efficiency standpoint. 

It meets all the requirements of this mechanism, and permits carrying 
out the best practices in the handling of the film from the stock room to the labo- 

In the designing of this spool our Mr. Mitchell had in mind not only the 
proper functioning of the camera as an individual production unit, but the entire 
train of procedure necessary to deHver the negative film to the printing stage in 
its best condition, and this fact is fast being realized and appreciated by the 
progressive producer as evidenced bj^ the support being given us by the entire 
industry today. 

It is hoped that your Standards Committee will adopt the measurements 
as we now use them for the reasons as given above and in our former letter. We 

142 Transactions of S.M.P.E., September 1925 

shall continue to use them without change after the success we have had with 

It will be impossible for our Mr. Mitchell to attend your spring meeting; 
however, he wishes for the success of your convention and knows that a great 
amount of good will be accomplished. 

Yours very truly, 

Mitchell Camera Corporation 
By H. F. Beger 

361 W. Ontario St. 
Chicago, 111. 

May 11, 1925 
Mr. John G. Jones 
Rochester, N. Y. 
Dear Sir: 

In reply to your letter of April 7 with regard to the matter of camera cores 
which is to come up at your spring meeting of the Society of Motion Picture 
Engineers, we beheve your position to be well taken as this would help matters to 
some extent to have the camera cores a trifle smaller to permit a roll of negative 
film to be placed on the camera core after the wooden core has been removed from 
the film. 

If care is taken by the operators not to get the camera core mixed with 
those sent by the raw film manufacturers so it is our opinion this improvement 
would hardly be practical. 

If it is decided to change standard to 31/32, we would suggest that the 
selling date for making them a considerable time ahead to help us reduce our 
stock of old style parts. 

This change, of course, will work quite a hardship on camera manufacturers 
as it makes it necessary to either discard or rework considerable stock. 

Very truly yours, 

Universal Camera Company 
By N. Cassidy 

Mr. John Jones: I think that the diameter of the core is part 
of the design of the camera, and in some cameras they have to rewind 
the negative film on the core in order to run the film right. 

Mr. Renwick: I move that these letters be published in the 
Transactions of our Society and that action be deferred. 

Motion carried. 

Mr. Porter: We are again taking up with the American 
Engineering Standards Committee the matter of getting our standard 
adopted, but in view of the amount of material which has been re- 
ferred back, I think we had better wait until some of it has been 

Discvssion - 143 

There is to be an international meeting on motion picture matters in Paris 
this coming June. ^Ye understand that Dr. Mees and Mr. Renwick are going to 
attend this meeting. We recommend that the Society take advantage of this 
opportunity and authorize them to officially represent us in connection with 
international matters of standards and nomenclature. 

Dr. Stoey: I move that 'Mv. Renwick and Dr. Mees be author- 
ized to act for the Society at the International Convention in Paris 
this summer with authority to submit to them our standards akeady 
adopted and to agree to any decision by that conference in accordance 
with our standards tentatively adopted but without including mechan- 
ical tolerances. 

Motion seconded. 

Dr. Mees: I should like to ask that the Society elucidate the 
matter. May I point out that the jurisdiction of the International 
Congress is only advisorj^ and not binding on any country. If w^e go 
as representatives of the Society, the agreements we make will be 
only with the International Congress and will not be standards of 
this Society and will not be binding on this Society. If you send us 
with a free hand, we mil attempt to have the international standards 
acceptable to this Society, but if not acceptable to this Society, I 
shall stiU attempt to get an international standard adopted rather 
than not have any. If we go bound not to accept anj^thing other 
than yom- standards, unless the International Committee accept 
them, we should have to leave the conference without voting. 

Me. Porter: It seems to me that Dr. Mees and Mr. Renwick 
are men of sufficient standing, reputation, judgment, and knowledge 
of motion pictures here and abroad so that the Societ}^ can give them 
their confidence. I suggest that the Society recommend Dr. Mees and 
Mr. Renwick go with authority to act and leave it to their judgment. 
If we do not do this, it will be like a political conference standing in 
the way of progress. This congress is intended to advance progress 
in the art. 

Mr. Davidsox: I agree with Mr. Porter and I make the amend- 
ment that the men be sent from the Society with authority to act at 
their discretion. 

President Joxes: I should like to point out that the amend- 
ment is contrary to the original motion. May I suggest that if you 
do not like the motion you vote accordingly. Do you wish to with- 
draw the original motion? Second withdrawn. 

144 Transactions of S.M.P.E., Septemher 1925 

Dk. Story: In the light of what has been said, I withdraw my 

Mr. Porter: I make the motion that the Society authorize 
Dr. Mees and Mr. Renwick to represent us at the International 
Congress with full power to act. 

Motion duly carried. 

Dr. Mees: May I ask what the recommendations of this 
Society are on the international standardization of sprockets? That 
question will come up, and I have no instructions on that. 

Mr. John Jones: It was agreed that we favor standardizing 
sprockets. What those standards will be is a matter of question. 
There is lots of work to be done in connection with the size of sprocket 
according to the position in which they are to function. 

President Jones: It seems to me that Dr. Mees and Mr. 
Renwick may wish instructions on points which have not come up 
here. We have a committee which has given the matter very careful 
consideration and know a great deal about it, and I think it would 
be desirable for this body to empower our Standards Committee 
to consult with Dr. Mees and Mr. Renwick and give them any 
necessary instructions and advice. I think it is unnecessary for us 
to go through all that here. 

Mr. Porter: We shall be gald to do anything w^e can to help. 

In closing, I should like to say that I have had the pleasure and 
privilege of serving on many different committees. Generally the 
Chairman does most of the work. Not so with this Committee, the 
members are workers, and I certainly want to thank personally the 
members of this Committee for their whole-hearted support and 

Dr. Mees : Before leaving the report, I think the Society should 
pass a vote of thanks to the Chairman and members of the Standards 
Committee. It is comparatively easy to read a paper, but the prepara- 
tion of a report is a tremendous piece of work, and then we tear it 
to pieces and send it back and ask the Committee to do it again, so 
I propose that the Society give them a vote of thanks. 

Motion carried. • 


With the No. 20 Transactions, the present Publication Com- 
mittee has rounded out one year of activity and has had pubKshed 
three issues. These volumes have not been up to the desired standard 
for a good many reasons. However, less delay and effort was ex- 
perienced by the Committee in publishing the No. 20 Transactions 
than for previous issues. A little care and consideration on the part 
of the authors would even further reduce the work of the Publication 
Committee. As all work must be done by the Committee either after 
hours or sandwiched in with regular business, the Committee would 
like to suggest that the authors give particular attention to the 
following outlines: 


A. Title. — The title of a paper should be as short as possible, 
but should be indicative of the nature of the text. 

B. Author^ s Name. — The author should give his full name. 

C. Author's Affiliation. — Company afhhation should appear as 
a footnote on the first page. 

D. Origin of Paper. — Communication number or place of issue 
should appear as a footnote on the first page. 

E. Illustrations. 

1. Illustrations should be used only when required to 
elucidate the text of a contribution. 

2. Cuts should be clearly marked showing to what part 
of the text they refer and where located in the text. 

3. The importance of cuts should be marked as an aid in 
determining their relative size. 

F. Captions.' — A number and a caption or explanation should 
be given for each picture, diagram and table. 

G. Formulae. — Equations, formulae, etc., should be given in 
the exact form desired by the author. Where abbreviations are used 
they should be consistent throughout. 

H. Pagination. — Each page should be numbered consecutively. 
I. Summary. — A summary should be given at the end of each 
paper showing the number of pages and the number of cuts. 



Transactions of S.M.P.E., September 1926 

A large part of the time of the Committee is taken up in the 
proper placing of cuts, sorting of cuts, captions, proper titling of 


Fig. 1. 

manuscript, securing author's full name and company affiliations, etc. 
All of this work may be obviated with very slight additional work 
by the author. 

Report of Pvhli cations Committee 147 

There has been some criticism on the part of members, of the 
delay of issuance of the Transactions. In order that you may see 
just where these delaj^s occur, we have prepared a time table. 

An examination of the time table shows clearly where delays 
occur. As the minimum time from the receipt of the papers to the 
issuance of the Transactions is forty days, it is most important that 
all papers be in the hands of the Publication Committee not more 
than ten days after the convention closes. It will then be possible 
with the proper co-operation from the authors to issue the first 
number in two months, and the second number at the most desirable 
time, probably one month prior to the next convention. Even though 
the Transactions are printed in two issues, it is desirable to have all 
material in promptly so that the papers may be grouped to form a 
well balanced volume. For the last convention, the papers which 
were handed in fii'st made up the first volume (No. 19), with the 
results that the No. 19 issue included sixty-nine typed pages and 
eleven cuts, the No. 20, one hundred typed pages and forty-three 

The growth and dignity of the society would seem to warrant a 
little more attention given to the Transactions. The Publications 
Conamittee offers as suggestions: 

(a) That an introduction be prepared for the coming issues, 
probably in the form of an editorial or editorials written by influential 
persons in the motion picture field together with abstracts of articles, 
pertinent to Motion Picture Engineering. ^luch of this data is 
already prepared and issued by the Eastman Kodak Company, 
National Lamp Works, Edison Lamp Works, and Westinghouse 
Lamp Company, etc., and a conamittee of one to collect such data, 
might be appointed by the chairman. 

(b) That the Transactions be set up in ten point leaded type 
instead of solid. The cost in printing will be increased about 17 per 
cent (forty and forty-eight lines per page) but part of this increase 
can be eliminated by allowing the discussion to follow immediately 
after the paper rather than placing it on a separate page. In fact this 
will compensate almost entu-ely, as many pages of the discussion 
occupy only a paragraph or two and all papers do not end at the 
bottom of a page. 

May 15, 1925. 

Fall Convention 


Society of Motion Picture Engineers 


Lakewood Farm Imn, 

Roscoe, New York 
October 5-8, 1925 

Everybody had a good time at Roscoe during the 1924 

Spring Convention and the demand for another meeting 

at the same place seemed so universal that it was selected 

for our Fall Convention. 

Golf, tennis, bowling, billiards and trapshooting! 

Saddle horses are available for rides through the mountains ! 

Fireproof garage. 

For further information see Bulletin and Trade papers. 


J. C. Kroesen, Chairman Arrangements Committee 







Officers, Committees 3-4 

List of Members 5 

Presidential Address. By L. A. Jones 9 

Report of the Progress Committee 1924-1925 17 

The Prefocusing Base and Socket for Projection Lamps. " ^ 

By R. S. Burnap 39 

An Exhibitor's Problems in 1925. By E. T. Clarke 46 

Washing Motion Picture Film . By K. C. D. Hickman ... 62 
A New Camera for Screen News Cinematographers. By 

J. H. McNabb 77 

Telephone Picture Transmission. By H. E. Ives 82 

Importance of the Village Theatre. By F. H. Richardson. 85 
Reflector Arc Projection — Some Limitations and Possi- 

bihties in Theory and Practice. By Sander Stark .... 94 

Advertisements 115 





Number Twenty -three 

MEETING OF OCTOBER 5, 6, 7, 8, 1925 









Number Twenty-three 

MEETING OF OCTOBER 5, 6, 7, 8, 1925 

|Iki f=n[===n =1 1 =1 1 n ir ir- i r=if=iJ 

J. I. Crabtrea 

L. C. Porter 

F. H. Richardson 

J. C. Kroesen 

J. C. Kroesen 

Geo. A. Blair 

L C. Porter 

J. C. Kroesen 
R. S. Peck 



C. E. Egeler, Chairman 
Rowland Rogers 
W. V. D. KeUey 

Standards and Nomenclature 
J. G. Jones, Chairman 
H. P. Gage 
C. M. Williamson 

P. M. Abbott, Chairman 
Geo. A. Blair 
R. S. Peck 

Wm. F. Little, Chairman 

J. C. Hornstein, Chairman 
J. C. Kroesen 
P. M. Abbott 

J. I. Crabtree, Chairman 
C. E. Egeler 

A. C. Dick, Chairman 
F. H. Richardson 
Earl J. Denison 

Kenneth Hickman 

C. A. Ziebarth 
Herbert Griffin 

F. H. Richardson 

J. A. Summers 

W. V. D. KeUey 

L. A. Jones 

Wm. C. Kunzman 


Abbott, P. M. (M) 

729 7th Ave., New York, X. Y. 
Abrahams, Leonard (A) 

251 West 19th St., Xew York, X. Y. 
Akeley, Carle E. CM) 

244 West 49th St., Xew York, X. Y. 
Alex.\xder, Dox M. CSl) 

Alexander Film Co., Denver, Colo. 
AiLEE, Joseph (M) 

5515 ]vIelrose Ave., Los Angeles, Calif. 
Ball, Joseph A. (M) 

1006 X. Cole Ave., Hollywood, Calif. 
Barbier, PArL L. C. CM) 

Pathe Cinema 30 rue des Yignerons, Vin- 
cennes (Seine), France 
Bassett, Preston R. (M) 

Sperry GjTOSCope Co., Manhattan Bridge 
Plaza, Brooklvn, X. Y. 
Beattt, a. M. (A) 

6S4 Franklin Ave., Xutley, X. J. 
Becker, Albert (A) 

146 Pearl St., Buffalo, X. Y. 
Beechltn, John T. (M) 

233 :Main St., Worcester, Mass. 
Benford. Frank (M) 

General Electric Co., Schenectadv, X'. Y. 
Bertram, E. A. (A) 

1339 Diversey Parkway, Chicago, 111. 
Bethel, James G. C^) 

Kiddle & IMorgison, 115 Broadway, X. Y. 
Blair, George A. (M) 

343 State St., Rochester, X. Y. 
Bltmberg, Harry (A) 

262 Xorth 13th St., Philadelphia, Pa. 
Bowen, Lester (A) 

440 Terrace Ave., Hasbrouck Heights, X. J. 
Bradshaw, a. E. (A) 

1615 Sixth Ave., Tacoma, Wash. 
Beenkert, Karl 'SI. TM) 

49 Cortland Ave., Detroit, Mich. 
Briefer, Michael (M) 

Atlantic Gelatin Co., Woburn, Mass. 
Bristol, William H. (M) 

Bristol Company, Waterbury, Conn. 
Brown, DorcLAS (A) 

121 East 40th St., Xew York, X. Y. 
BrcKLES, J. 0. (A) 

1912 West 12th St., Oklahoma City, Okla. 
BuRNAP, Robert S. (M) 

Edison Lamp Works, Harrison, X. J. 
Bush, Herman (A) 

1327 S. Wabash Ave., Chicago, 111. 
Campe, H. a. fM) 

5550 Rahegh St., Pittsburgh, Pa. 
Candy, Albert M. (M) 

Westinghouse Elect. & Mfg. Co., E. Pitts- 
burgh, Pa. 
Capstaff, John G. (M) 

Eastman Kodak Co., Rochester, X. Y. 
Carleton, H. O. (A) 

Harris Ave. & Sherman St., Long Island 
City, X. Y. 
Carpenter, Arthur W. (A) 

350 Madison Ave., X'ew York, X. Y. 
Chanier, G. L. (M) 

1 Congress St., Jersey City, X. J. 
Cifre, J. S. (M) 

26-28 Piedmont St., Boston, :Mass. 
Clark, James L. (SI) 

244 West 49th St., Xew York, X. Y. 
Clarke, Eric T. (A) 

Eastman Theater, Rochester, X. Y. 

Cohen, Joseph H. (M) 

Hill St., Woburn, :Mass. 
CoNKLiN, Robert (A) 

SOO Boulevard East, Weehawken, X. J. 
Cook, Willard B. (M) 

35 West 42nd St., Xew York, X. Y. 
Cook, Otto W. (M) 

Research Lab. Eastman Kodak Co., Roches- 
ter, X. Y. 
CozzENS, Louis S. (A) 

DuPont De Xemours Co., Parlin, X'. J. 
Crabtree, John I. (M) 

Eastman Kodak Co., Kodak Park, Rochester, 
X. Y. 
CuMMiNGS, John S. C^) 

Harris Ave. & Sherman St., Long Island 
Citv, X. Y. 
Davidson, -L. E. (M) 

Spencer Lens Co., Buffalo, X". Y. 
Denison, E.arl J. (M) 

4S5 Fifth Ave., Xew York, X. Y. 
DeTartas, Augustus R. (A) 

Grosvenor St. & East Drive, Douglas Manor, 
L.I., X. Y. 
DeVault, R.4iPH P. CM) 

Acme ]\Iotion Picture Projector Co., 1134 W. 
Austin Ave., Chicago, 111. 
DeWitt, H. X. (A) 

156 King St. W., Toronto, Canada. 
Dick, A. C. (A) 

Westinghouse Lamp Co., 150 Broadway, 
Xew York, X. Y. 
Donaldson, Wm. R. (A) 

30 Pine St., Xew York, X. Y. 
Dunbaugh, Geo. J. (A) 

7332 Kimbark Ave., Chicago, 111. 
Earle, Robert D. (^I) 

Bay State Film Co., Sharon, Mass. 
Egeler, Carl E. CM) 

X'ational Lamp Works Engineering Dept., 
X'ela Park, Cleveland, Ohio. 
Elms, John D. C-^) 

59 Mechanic St., X'ewark, X*. J. 
Faulkner, Trevor (A) 

485 Fifth Ave., Xew York, X. Y. 
Flynn, Kirtland (M) 

290 Ferry St., Xewark, X. J. 
Fritts, Edwin C. (M) 

Eastman Kodak Co., Rochester, X. Y. 
Fulcher, Edgar J. C-^) 

157 Albert Street East, Sault St. ^larie, 
Ontario, Canada. 

Fulton, C. H. (A) 

c/o E. E. Fulton Co., 1018 South Wabash 
Ave., Chicago, Illinois. 
Gage, Henry P. (M) 

Corning Glass Works, Corning, X. Y. 
Gage, Otis A. (A) 

Corning Glass Works, Corning, X. Y. 
GAUiioNT, Leon (M) 

57 Rue Saint Roch, Paris, France. 
Gelman, J. X. (M) 

3449 Jay St., Cincinnati, Ohio. 
Glover, Harry M. R. CM) 

Gundlach Manhattan Optical Co., Rochester, 
X. Y. 
GoFF, Daniel J. C^) 

3668 S. Michigan Ave., Chicago, 111. 
Goldberg, J. H. (A) 

3535 Roosevelt Rd., Chicago, 111. 
Goldman, Lyle F. (A) 

350 Madison Ave., Xew York, X. Y. 

Transactions of S.M.P.E., Januanj 1926 

Gray, Arthur H. (M) 

Lancaster Theatre, Lancaster & Causeway 
Sts., Boston, Mass. 
Green, Walter E. (M) 

Precision Machine Co. Inc., 317 East 34th St. 
New York, N. Y. 
Greene, Chauncey L. (A) 

2403 Aldrich Ave., South MinneapoUs, Minn. 
Gregory, Carl Louis (M) 

76 Echo Ave., New Rochelle, N. Y. 
Griffin, Herbert (M) 

90 Gold St., New York, N. Y. 
Halverson, C. a. B. (M) 

General Electric Co., West Lynn, Mass. 
Hamister, Victor C. (M) 

National Carbon Co., 117th & Madison Ave., 
Cleveland, Ohio. 
Handschlegl, Max (M) 

1040 McCadden Place, Los Angeles, Cahf. 
Harrington, Thomas T. (M) 

2242 Grove St., Berkeley, Calif. 
Hedwig, William K. (M) 

Rex-Hedwig Laboratories Inc., 220 West 
19th St., New York City. 
Hertner, J. R. (M) 

1905 West 114th St., Cleveland, Ohio. 
Hibbard, Frank H. (M) 

Duplex Motion Picture Industries, Harris 
Ave. & Sherman St., Long Island City, 
N. Y. 
Hickman, Kenneth (M) 

Kodak Park, Rochester, N. Y. 
Hill, Roger M. (M) 

458 State War & Navy Building, Washington, 
D. C. 
HiTCHiNS, Alfred B. (M) 

Duplex Motion Pictures Inc., Sherman & 
Harris Ave., Long Island City, N. Y. 
HoLMAN, Arthur J. (A) 

56 Cummings Read, Brookline, Mass. 
HoRNiDGE, Henry T. (A) 

Kiddel & Morgison, 115 Broadway, New 
York, N Y. 
Hornstein, J. C. (A) 

740 7th Ave., New York, N. Y. 
Howell, A. S. (M) 

1801 L^rchmont Ave., Chicago, 111. 
Hubbard, Roscoe C. (M) 

203 West 146th St., New York, N. Y. 
Hubbard, Wm. C. (M) 

111 W. 5th St., Plainfield, N. J. 
HuESGEN, Charles K. (A) 

18 East 42nd St., New York, N. Y. 
Hutchinson, Miller R. (M) 

90 West St., York, N. Y. 
Hutchinson, Wm. M. (A) 

Box 576 Sherman, Calif. 
Ives, F. E. (M) 

1808 N. Park Ave., Philadelphia, Pa. 
Jeffrey, Frederick A. (A) 

9 Giles St., Toovak, South Australia 
Jenkins, Francis C. (M) 

5502 16th St., Washington, D. C. . 
John, Robert (M) 

229 West 28th St., New York, N. Y. 
Johnstone, W. W. (A) 

28 Geary St., San Francisco, Calif. 
Jones, John G. (M) 

Eastman Kodak Co., Rochester, N. Y. 
Jones, L. A. (M) 

Eastman Kodak Co., Rochester, N. Y. 
Kelley, Wm. V. D. (M) 

43 Tonnelle Ave., Jersey City, N. J. 
Kellner, Dr. Herman (M) 

635 St. Paul St., Rochester, N. Y. 
Keuffel, Carl W. (A) 

3rd & Adams St., Hoboken, N. J. 
Kroesen, J. C. (M) 

Edisoij Lamp Works, Harrison, N. J. 

Kunzmann, Wm. C. (M) 

Suite 2-2992 West 14th St., Cleveland, Ohio. 
Lair, C. (M) 

Pathe Cinema 30 Rue des Vignerons, 
Vincennes, France. 
Lang, C. J. (M) 

Lang Mfg. Works, Olean, N. Y. 
La Rue, Mervin W. (A) 

156 King St. W., Toronto, Canada. 
Leventhal, J. F. (M) 

1540 Broadway, New York, N. Y. 
Little, W. F. (M) 

80th St. & East End Ave., New York, N. Y. 
McAuley, J. E. (M) 

552 W. Adams St., Chicago, 111. 
McGiNNis, F. J. (A) 

Box 541, Palm Beach, Fla. 
McNabb, J. H. (M) 

Bell & Howell Co., 1801 Larchmont Ave., 
Chicago, 111. 
Mailey, R. D. (A) 

Cooper Hewitt Electric Co., Hoboken, N. J, 
Maire, Henry J. (A) 

2152 Center Ave., Fort Lee, N. J. 
Manheimer, J. R. (M) 

155 East 44th St., New York, N. Y. 
Marette, Jacques (M) 

Technique de Pathe Cinema 30 Rue des 
Vignerons, Vincennes, France. 
Mayer. Max (M) 

218 West 42nd St., New York, N. Y. 
Mechau, Emil (A) 

E. Leitz, Inc., Rastatt, Germany. 
Mees, Dr. C. E. K. (M) 

Eastman Kodak Co., Rochester, N. Y. 
Miller, Arthur P. (M) 

Rothaker Film Co., 1339 Diversey Parkway, 
Chicago, 111. 
MiSTRY, D. L. (A) 

4 Nepean Rd., Malabar Hill, Bombay 6, 
MiSTRY, M. L. (A) 

4 Nepean Road, Malabar Hill, Bombay 6, 
Mitchell, Geo. A. (M) 

6025 Santa Monica Blvd., Los Angeles, Cal. 
Moloney, Fred G. (M) 

7544 S. Chicago Ave., Chicago, 111. 
Murphy, E. F. (M) 

Palisade Film Lab., Lin wood Ave., Fort Lee, 
Nelson, Otto (A) 

National Cash Register Co., Daj'ton, Ohio. 
Nixon, Ivan L. (M) 

Bausch & Lomb Optical Co., Rochester, N. Y 

130 West 46th St., New York, N. Y. 
NoRRisH, B. E. (M) 

12 Mayor St., Montreal, Canada. 
Olesen, Otto K. (M) 

1645 Hudson Ave., HoUvwood, Calif. 
Palmer, M. W. (M) 

6th & Pierce Aves., Long Island City, N. Y. 
Patterson, Leo J. (M) 

4445 Sunset Blvd., Los Angeles, Calif. 
Peck, Raymond S. (]M) 

Dept. of Trade & Commerce ^Motion Picture 
Bureau, Ottawa, Canada. 
Pennow, Willis A. (A) 

209 South St., Oconomowoc, Wisconsin. 
Peyton, John T. (A) 

116 S. Hudson St., Oklahoma City, Okla. 
PoMEROY, Roy J. (M) 

1520 Vine St., Hollywood, Calif. 
Porter, L. C. (M) 

Edison Lamp Works, Harrison, N. J. 
Posey, O. D. (A) 

58y2 Cone St., Southern Enterprise Inc., 
Atlanta, Ga. 

List of Members 


Warner Research Lab., 461 Eighth Ave., 
New York, X. Y. 
Peatchett, a. B. (A) 

Caribbean Film Co., Animas 18, Havana, 
Price, Aethitr (A) 

130 Denhoff Ave., Freeport, L. I. 
Proctor, B. A. ^I) 

2955 Grand Concourse, Xew York, X. Y. 
QuiXLAX, Walter (M) 

55th St. & 10th Ave., Xew York, X. Y. 
Rabbell, Wm. H. (M) 

729 7th Ave.. X'ew York. X'. Y. 
Raess, Hexry F. fA) 

Warner Research Lab., 461 Eighth Ave., 
Xew York, X. Y. 
Raxsdell, RrssELL R. fA) 

5408 Pasep Boulevard, Kansas Citv, Mo. 
Ravex, a. L. (M) 

1476 Broadwav, Xew York, X". Y. 
Redpath, Wm. CM) 

156 King St. W., Toronto, Canada. 
Reich, Carl J. (M) 

Gundlach-Manhattan Optical Co., 739 Clin- 
ton Ave. South, Rochester, Xew York. 
Rexwick, F. F. (A) 

Ilford Ltd., Ilford, Essex, England. 


516 Fifth Ave., Xew York, X. Y. 
Rogers. Rowlaxd (A) 

71 West 23rd St., Xew York, X. Y. 
Rose. S. G. (M) 

Victor Animatograph Co., Davenport, Iowa. 
RossMAX, Earl W. CM) 

Citv Club of Xew York, 55 West 44th St., 
Xew York. X. Y. 
Roth ACKER, W. R. iM) 

1339 Diversev Parkway, Chicago, 111. 
Rub EX, Max (A) 

2105 John R. St., Detroit, Mich. 
RrDOLPH, Wm. F. (A) 

1520 Vine St., Los Angeles, CaUf. 
RuoT, Marcel (A) 

5 Lisle Street, London, W. 1, England. 
Savage, F. M. (A) 

1476 Broadwav, Xew York, X. Y. 

Box 86, DuPont De XemoursCo., Parlin,-X.J. 
ScHMiTz, Erxest C. (A) 

39 Avenue Montaigne, Paris, France. 
Sexxer, Adolph G. (A) 

Herbert & Huesgen Co., 18 East 42nd St., 
Xew York, X. Y. 

Serrurier, Iwax (M) 

1803 Morgan Place, Los Angeles, Calif. 
SiSTROM, William CSl) 

Metropolitan Pictures Corp. 1040 Los 
Palmas Avenue, Hollywood, Calif. 
Slomax, Cheri M. CA) 

East 3000 Woodbridge St., Detroit, Mich. 
Spexce, Johx L. CM) 

250 West 49th St., Xew York, X. Y. 
Stoxe. George E. (M) 

Carmel, Monterey County, Calif. 
Story, Dr. W. E. CM) 

17 Hammond St., Worcester, ^lass. 
Struble, Corxelius D. (M) 

108 West 18th St., Kansas City, Mo. 
Summers, Johx A. (M) 

Edison Lamp Works, Harrison, X. J. 
Swaab, Mark L. (A) 

1325 Vine St., Philadelphia, Pa. 
Theiss, Johx H. (M) 

DuPont Co., Box 144, Parlin, X. J. 
Thomas, A. L. (A) 

Box 21o, Auburn, Ala. 
Topliff, Geo. W. (A) 

Ansco Co., Binghamton, X. Y. 
Towxsexd, Lewis ^1. (M) 

Eastman Theatre, Rochester, X. Y. 
Travis, Charle.s H. (A) 

131 Lniversity Place, Schenectady, X. Y. 
L'rbax, Charles M. i'M) 

L'rban-Kineto Corporation Irvington-on- 
Hudson, X'ew York. 
Victor. A. F. (M) 

242 W. 55th St., Xew York, X. Y. 
VixTEX, Wm. C. (M) 

89 Wardour St., London, W 1, England. 
Waller, Fred QI) 

Famous Players-Lasky Corp., Sixth and 
Pierce Ave., Long Island City, X. Y. 
Wescott, W. B. (M) 

Dover, Mass. 
Williamson, Colix ^M. (A) 

Williamson ]vlanufacturing Co., Ltd., Litch- 
field Gardens. London, X. W. 10, England. 
WiLLAT, C. A. (M) 

1803^2 Gower St., Hollywood, Calif. 


115 Broadway, Xew York, X. Y. 
Wtckoff, Alvix a. QI) 

Famous Plavers-Laskv Corp., Astoria, L.I., 
X. Y. 

ZlEBARTH, C. A. (M) 

1801 Larchmont Ave., Chicago, 111. 


Roscoe, New York, October 5, 1925 

IT IS with a feeling of genuine pleasure that I come before you once 
more to say a few words in opening our annual autumn convention. 

This, I beheve, is the twenty-first regular meeting of the Society, 
and since it is our custom to meet twice each year, it follows that 
we are just entering the eleventh year of our existence. We are 
therefore a relatively 3"oung organization, and I feel that we should 
all be very proud of the great progress which has been made in this 
relatively short period of time. 

In this swiftly moving twentieth century, most of us as indi- 
viduals lead lives that are filled full to overflowing with work and 
play. We are swept onward by a rapidly moving tide of events 
with Httle opportunity to consider whence we have come and whither 
we are going. While in general it is futile to look backward into the 
past or to attempt to speculate on what the future may hold, it is 
desirable sometimes to pause a little and to consider how far we have 
come and to plan the course to be followed in the future. 

Our Life as an organization is similar to that of the individual. 
The motion picture industry has grown so rapidly, inventions and 
improvements have come so thick and fast, that we as a society have 
been completely occupied in our attempt to keep up with the pro- 
cession and we have had little time to dehberately consider the 
progress we have been making. We have been busy with the details 
of our daily society hfe, planning for meetings, getting the papers 
program ready, publishing the Teansactioxs, collecting dues, hunt- 
ing for new members, and all such things necessary to the welfare of 
our organization. It may be worth while, therefore, to pause a little 
and consider our present position. Perhaps we might ask ourselves 
such questions as these: Are we proceeding in the right direction? 
How much of what we set out to do has been accompUshed? What 
remains to be done? Has our growth been as great as could be ex- 
pected? In what directions lie the most fruitful fields for future work? 

Before attempting to answer these questions, let us refresh our 
memories as to the purpose for which the Society was organized. 
In the words of the framers of our constitution the object of our 


10 Transactions of S.M.P.E., January 1926 

existence is "Advancement in the theory and practice of motion 
picture engineering and the aUied arts and sciences, standardization 
of the mechanisms and practices employed therein, and the main- 
tenance of a high professional standing among its members." Just 
how can we as a society contribute to the "advancement in the theory 
and practice of motion picture engineering?" Obviously, with our 
present financial recources we cannot hope to maintain a research 
laboratory; nor can we operate studios, laboratories, exchanges, or 
theatres, or in fact any of the actual units which compose the in- 
dustry. Our influence must, therefore, be more or less indirect. We 
must encourage, stimulate, and assist the individuals and corporations 
actually engaged in the production, distribution, and exhibition of 
motion pictures. 

This we accomplish largely by means of our semi-annual meet- 
ings at which papers dealing with theoretical and practical subjects 
of interest to many phases of the industry are read. These papers are 
published in the Transactions and hence reach many who cannot 
attend our meetings. In this way knowledge is disseminated, and a 
permanent reference library is being built up. The discussion of the 
papers are of no little value. They stimulate thought and frequently 
result in the birth of new ideas which later are developed and applied. 
The very fact that our papers committee has to work so hard to 
get papers for our programs proves that the work is valuable; for, 
if some individuals were not thus coaxed, cajoled, or bullied into 
writing papers, much highly specialized and valuable knowledge 
would never become available for the use of others. Frequently the 
individual does not realize that his knowledge is of great value to 
others. He becomes so familiar with the details of his own work that 
he does not realize its highly specialized character and that a knowl- 
edge of it might be of great interest and help to others working along 
the same lines. A very forceful illustration of this state of affairs 
came to my notice recently. It happened that I had the pleasure 
of visiting a large producing plant and of being shown many interest- 
ing things. A member of this organization, and one actively engaged 
in the production of motion pictures, had explained and demonstrated 
how a particular thing is accomplished which to me was of great inter- 
est and on which I am sure it would be impossible to find any ade 
quate information anywhere in the literature. On being asked why 
he did not write a paper for the S. M. P. E. describing this procedure, 
he replied that he did not suppose it would be of interest to anyone. 

Presidential Address — Janes 11 

It appears that there was no objection whatever to the pubHcation of 
the information, but he simply had not reahzed that it was of any 
value to anyone else. After considerable urging he agreed to prepare 
a paper for us on the subject which will probably be given at our next 
meeting. This exactly illustrates how valuable our activities may be 
in making available technical information. It also illustrates the 
difficulties with which our papers committee is confronted. There 
is no doubt that ample material is available for our programs. The 
question is how to find it, and to persuade busy men to prepare the 
material for publication. This illustrates also how difficult it is for a 
single individual, without the assistance of an active committee and 
other members of the society, to obtain the technical papers required 
for a well balanced program. No one person can be in intimate touch 
with all of the diverse phases of the motion picture industry, and 
it is only by the co-operation of several individuals that the best 
results can be obtained. 

In any large and growing industry standardization is of utmost 
importance. We have been very active in advocating standardization 
and in establishing standards for mechanism and practice. Much 
remains to be done, however, and I feel this is one of the activities 
of utmost irrportance, one which should be given a great deal of 
attention during the coming years. Efforts towards standardization 
in our own country have been fairly successful, but in an industry 
of such world-wide distribution national standardization is not 
sufficient. We must have international standards. We are in con- 
tinuous communication with the English, French, and German 
motion picture groups, and a start towards international standards 
was made at the Sixth International Congress of Photography held 
in Paris last July. Some action was taken the details of which will 
doubtless be set before you by Mr. Porter, the chairman of our 
Standards Committee. 

A permanent commission in America is to be formed to take 
care of arrangements for the Seventh International Congress which 
will probably be held in 1930. Dr. C. E. K. Mees, one of our own 
members, will probably be the permanent chairman of this commis- 
sion, and we as a Society have been asked to appoint one or two other 
representatives to serve on this commission. A definite logical 
program for standardization should be prepared for presentation at 
the next international congress, and it is not too soon to start active 
preparation of this. This is a matter which should be kept constantly 
in mind. 

12 Transactions of S.M.P.E., January 1926 

Thus far our efforts towards standardization have been con- 
cerned chiefly with mechanisms and film dimensions. This work 
needs to be greatly extended and broadened. Conditions under 
which motion pictures are projected are, at the present time, very 
diverse and in many cases unfavorable. There seems to be little 
doubt that great improvement can be achieved in this direction. 
The question of standardizing positive film density, screen brightness, 
reflection characteristics of screen surfaces, etc., has been discussed 
at various times in our sessions. Apparently there are many difl&- 
culties to be encountered in any such program. However, there is no 
reason to believe that these difficulties are insurmountable. We must 
admit, however, that the problem is a very complicated one. Many 
factors including not only purely objective quantities measurable by 
precise physical methods, but also some of a subjective nature 
involving laws of phj^siological and psychological optics must be 
considered. I do feel, however, that the matter should be given 
careful consideration, and while it may be impossible to establish 
rigid standards, I do believe that the average quality of the pro- 
jected picture can be greatly improved by the recommendation of 
ideal values with fairly wide tolerance limits. 

The question of membership growth is one that deserves serious 
attention. In 1922 we had a total membership of 180, while at the 
close of 1924 this had increased to 210. During the two years between 
the dates mentioned, a much larger number of new members were 
obtained, but the resignations occurring during that time kept the 
actual increase down to 30. The rate of growth of membership during 
the past two years is therefore much less than during the two or 
three years preceding 1922. The reason for this falling off in the rate 
of growth is not entirely self-evident. Is it a lack of activities on our 
part in going out after new members? Is it due to the fact that we 
have already drawn into the organization practically all of those 
available? Probably the answer is that it is due somewhat to each of 
these causes. While the motion picture industry on the whole seems 
to be enjoying a healthy growth, there is no doubt that it is tending 
to reach a condition of equilibrium and it is possible that the number 
f o individuals connected with the industry who are eligible to member- 
ship in our society is not increasing to any great extent. I feel that 
if we are to add materially to our membership we must do something 
to interest those in somewhat different fields of motion picture work 
tftan those to which most of us at present belong. I sometimes feel 

Presidential Address — Jones 13 

that the very name of our society, including as it does the word 
"engineers/' discourages from joining a great many men who really 
should be members and who would both benefit by association with 
us and bring valuable contributions to the organization. We have 
not been able apparently to interest sufficientlj^ men in the production 
and exhibition branches of the industiy. There is little doubt that 
many people working in these fields should be drawn into the organi- 
zation. I feel, therefore, that it is only by broadening the scope of 
our activities that we can hope to obtain an appreciable increase in 
membership. The future activities of the society, therefore, should 
be planned to go ahead not only with the type of work which we have 
been carr^dng on in the past but to branch out into other phases of 
the industry to which in the past we have given to 3 httle attention. 

This brings us face to face with the future. Along what lines 
should we attempt to extend our activities? Of course, I can only 
express my own opinion, and I do not feel that I am especially quali- 
fied to make authoritative statements on this subject. However, 
I have given the matter considerable thought and perhaps a few 
suggestions, even though they be tempered b}^ personal viewpoint, 
may be of value to those who in the future are to be responsible for 
our activities. Undoubtedly we may expect a certain increase in the 
number of motion picture theatres and a great improvement in the 
average quahty of these theatres. There is much valuable work that 
can be done in improving the production and exhibition of theatrical 
films. The question of architectural design of the theatre is one which 
I think should be given particular attention. In only a few cases have 
motion picture theatres been built according to the best possible 
design for the exhibition of motion pictures. I beheve that this 
society, by the use of judicious propaganda could have a profound 
influence toward the betterment of conditions, and this is one of the 
things on which I hope the Society will concentrate in the future. 

It is, however, in the non-theatrical field that I beheve the 
greatest future development wiU occur. The recent introduction of 
amateur motion picture photography has opened a tremendous 
field for the apphcation of motion pictures. I see no reason why 
we should not be as much or more concerned with this field than with 
the theatrical. 

The application of motion pictures to educational work is also 
just in its infancy. Here again our organization ought to find a fertile 
field for its endeavors. There is httle doubt that certain subjects 

14 Transactions of S.M.P.E., January 1926 

can be taught more efficiently by visual methods than by any other. 
There is much work to be done, however, in determining the best 
methods of using this new teaching device and how to make films 
particularly adapted to teaching purposes. Already the motion 
picture is being used in many of our best schools and universities for 
showing to entire classes things which in the past could be shown only 
to individuals and even then under rather unfavorable conditions. 
Motion pictures are being applied in almost every field of scientific 
research, and the possibihties, it seems, are practically unlimited. 

The use of the motion picture in advertising may also develop 
to great proportions. There seems to be little doubt that salesmen 
equipped with properly made films and projectors can appeal to 
their customers much more efficiently and persuasively than by 
any other method. This is another phase of development in which 
we should be vitally interested and which we should encourage. 

I have already suggested the desirability of broadening our field 
of activities. This, I feel, is so important that I wish to return to it 
again and pay particular emphasis to the need for such action. The 
majority of the membership of this Society consists of individuals 
who are interested largely in the technical scientific problems of the 
industry. Very few of us have any extensive knowledge of many of 
the problems involved in the making of a finished feature film. 
Nevertheless, we should be interested in these problems, and those 
who are particularly concerned with them should be interested in 
our part of the work. A better understanding and co-operation be- 
between all of those who contribute to the production of the film 
will undoubtedly be of benefit. Anything that will produce a closer 
co-operation between the producer, director, art director, lighting 
engineer, laboratory man, camera man, projectionist, distributor, and 
all those who at some point contribute to the production of a picture 
will react to the ultimate benefit of the industry and hence to the 
ultimate benefit of every individual connected therewith. We should 
be interested not only in the production of pictures which are better 
technically (that is from the standpoint of photographic and mechani- 
cal quality) but also from the standpoint of literary, dramatic, and 
moral character. The fact that we are not intimately concerned with 
the literary and dramatic material does not mean that we should be 
indifferent to its quality. I have heard the opinion expressed in a 
discussion relative to the quality of motion picture productions that 
the literary merit of the average motion picture is greater than that 

Presidential Address — Jones 15 

of the average novelistic literature being produced at the present time. 
The propounder of this statement, therefore, argues that the quahty 
of the motion picture is all that could be expected under these con- 
ditions. It seems to me this argument is not sound, for the modern 
motion picture need not depend on modern literature entirely for its 
subject matter when the best of literary efforts for the past several 
hundred years may be utilized. You may feel that it is entirely 
beyond our province to concern ourselves with subject matter, but 
I point out again that the statement of the object of our organization 
as found in our constitution is that we are supposed to contribute to 
the advancement not only of the theory ' and practice of motion 
picture engineering, but also to the allied arts and sciences. 

I feel that my remarks have been somewhat disconnected and 
that I am taking up entirely too much of your valuable time, and, 
while there is much more that could be said on this very interesting 
subject, I shall not pursue the argument further, but hope that 
what I have said may stimulate others of you to think along similar 

In this, my valedictory as your chief executive, I should show 
myself ungrateful indeed if I did not take the opportunity to express 
my thanks to those who have so ably assisted me during my adminis- 
tration. It has been a keen pleasure to do my part in conducting the 
affairs of the organization, and I can truthfully say that I have been 
loyally supported by every individual member. For this support and 
loyalty I render my best thanks. To the officers also I owe a great 
debt of gratitude for the way in which they have each discharged their 
duties. In no other organization with which I have been connected 
have I found such universal willingness on the part of the members to 
work for the society. If the two years of my incumbency of this 
office have been successful, it is due entirely to the loyal support 
of officers and members. It would be impossible to thank adequately 
all those who have assisted me. I do, however, wish to take this 
opportunity to express my thanks particularly to one or two who 
have, it seems to me, given most generously of their time and efforts. 
As you know, Mr. J. C. Kroesen has been chairman of the Publicity 
Committee for some time. He has given to this work many, many 
hours of his own time, and he has always been willing to take on even 
heavier burdens. I doubt if the Society has any conception of the 
amount of work involved in carrying on the activities of even so small 
an organization as ours. And to Mr. Kroesen I express my sincere 

16 Transactions of S.M.P.E., January 1926 

appreciation. The chairman of our PubUcation Committee also 
has a very difficult task, a task, in fact, which could be very materi- 
ally lightened by a Uttle more work and thought on the part of the 
contributors to our Transactions. To Mr. Little for his careful and 
efficient labors in connection with the publication of our Transac- 
tions, I also tender my most hearty thanks. The other committees 
have also worked diligently and to them I express my appreciation. 

1924-1925 Report of the Progress Committee 


THE ideal motion picture has been described as one which is 
projected stereoscopically in natural color, is free from flicker 
and rain effects, and is accompanied by audible reproduction of 
the players' words. We are still some distance from this ideal, but 
it gives us some idea why developments during the past year have 
been carried along a few principal lines in efforts to reach this goal. 
They include the production of many mechanical devices, in which 
the Germans have been especially active, marked interest in color 
photography, reduction of non-visible radiation in the light beam 
before it reaches the film, and more attention to the theatre per- 
formance along the lines of co ordination of the lighting effect, music, 
and screen picture. 

American competition is given as the cause for a revival in the 
building of theatres on the Continent.^ The larger cities of Germany, 
Spain, Holland, Belgium, Czecho-Slovakia, and the Balkan states 
have new theatres of the better class, capable of producing first class 
performances. Both in France and Germany the producers are 
active not only with new films, but also in buying the larger theatres 
of the principal cities. In France the musical accompaniment to the 
film production is receiving special consideration. 

In Europe considerable attention has been directed^ to the 
thirty year anniversary of the contributions of the Lumiere brothers 
to the field of cinematography. Special attention has been given to 
their mechanical developments, and credit is given for the technical 
principles of modern practice to the work of these two men. 

Increasing use of the motion picture^ in the field of medicine is 
shown by the taking of motion pictures of the interior of the bladder. 
They were obtained with the use of a cj^stoscope combined with a 

1 Mov. Pict. World, March 21, 1925, p. 228. 

2 Kinotechnik, IMarch 10, 25, April 25, 1925, pp 106, 137, 187 and other 

3 Sci. Ind. Phot., January 1925, p. 7. 
Kinotechnik, November 10, 1924, p. 402. 


18 Transactions of S.M.P.E., January 1926 

camera; as the crank is turned the cystoscope rotates, permitting a 
circular exploration. 

Respectfully submitted, 

C. E. Egeler, Chairman 

P. R. Bassett 

W. T. Brattn 

J. I. Crabtree 

Rowland Rogers 


Announcement was recently made of an improved motion picture 
camera^ for amateur use which employs 16 mm width film, weighs 
only 5 pounds, and is little larger than a Kodak. 50 or 100~foot 
lengths of film may be used and the camera loaded in dayhght; it 
is spring driven. The type of view finder employed allows the 
camera to be held at waist level. An exposure guide and a footage 
indicator are included. The exposure lever may be locked in oper- 
ating position so that the user can place the camera on a firm 
support and include himself in the action. 

A so-called "process camera"^ has been developed which is 
capable of securing unusual results in trick photography. Among the 
effects produced are those of ''suspended motion," where one image 
is held indefinitely on the screen, and reverse motion or reversal of 
action without break in the continuity. The production of multiple 
images of various sizes is another feature of the camera. With a new 
professional model camera^ direct focusing on the film or at the 
aperture on a ground glass is possible, without the necessity of swing- 
ing the lens out of position or moving the front vignetting attach- 

A number of camera devices^ have been developed in Europe, 
among which is a triple revolution counter of German manufacture 
for attachment to motion picture cameras to facilitate the taking of 
trick pictures and especially double exposure effects. It obviates the 
necessity in this work for the camera man to watch the revolution 
counter during the taking of a scene. 

^ Amer. Cinemat., August 1925, p. 6. 
5 Mot. PicL News, February 14, 1925, p. 716. 
^ Amer. Cinemat., November 1924, p. 25. 
^ Kinotechnik, November 25, 1924, p. 430. 

Report of the Progress Cofnmittee 1924-25 19 

A range finder^ suitable for attachment to a motion picture 
camera is of marked aid to the cinematograph er. It works on a 
principle similar to that of the large range finders used in the Navy. 

In an improved German camera the new features^ of easily 
interchangeable objectives, a pressure roller at the gate, and a range 
finder are employed. The end of a scene is marked by a perforation 
at the edge of the film. The size of the image in the finder changes 
with a change in objective. Another camera^° recently placed on the 
market may also be used as a printer, projector, and enlarger by the 
use of simple auxiliary apparatus. An amateur type camera^^ meas- 
ures 9X10.5X4 cm. and weighs 700 g. A fixed focus lens works at 
f/3.5. A German amateur apparatus^^ is said to combine the functions 
of a motion picture camera, "still" picture camera, projector, en- 
larging device, printer, and rewinding device. It uses a standard 
size film. Lightness in weight^-^ is the outstanding feature of a new 
French camera. 

Color Photography 

The Szczepanik^^ three-color additive process for colored motion 
pictures was demonstrated early this year. The three-color records 
are obtained on the negative b}^ means of a special camera in which 
the fihn moves continuously behind a large lens of a diameter some- 
what greater than the height of the three frames. Small lenses, each 
of which is provided with one of the color filters, red, green, or blue, 
move with the fihn behind the large lens. In this manner the three- 
color records are obtained in succession on the negative. It is claimed 
that optical parallax and color fringes are largely eliminated, since 
several successive frames are always being exposed at any given 
instant. For projection a similar optical system is employed, but the 
definition falls below that obtained with black and white film pro- 
jectors. Some flicker and lack of color balance were noticeable. 

8 Kinotechnik, July 10, 1924, p. 209. 

^ Kinotechnische Rund., January 1925, p. 8. 

" Rev. d'Opt., November 1924, p. 499. 

Kinotechnik, January 10, 1925, p. 7. 
11 Rev. d'Opt., July 1924, p. 342. 

^ Die Photographische Industrie, June 23, 1924, p. 515. 
13 Bulletin de la Societe franqaise de Photographie, April 1924, p. 86. 
" Kinotechnik, February 15, 1925, p. 61. 

Kinotechnik, April 10, 1925, p. 157. 

20 Transactions of S.M.P.E., January 1926 

A new German film for three-color photography^^ dispenses with 
color filters. The usual filter dyes are placed on the film in bands 
at the proper intervals for the three monochrome images which 
appear in series. The negative is developed in the usual manner and 
the positive print made, which is projected additively through a 
rotating disk bearing red, green, and blue sections. The standard 
camera and projector are employed. Another color film^^ is made 
from two separate color negative records taken simultaneously by 
means of a beam-splitting prism placed in the camera. One record 
is made from a mixture of red, orange, and yellow light and the other 
from a mixture of yellow, green, blue, and violet light. 

In a four-color additive projection system^^ developed in Great 
Britain, enlarged images are each in turn projected through a separate 
focussing lens. Higher screen illumination than is ordinarily obtained 
results, as the separate lenses may be made of larger diameter than is 
customary. Another British two-color subtractive process^^ utilizes 
the principle of cementing in register two separate and complemen- 
tary images on two film bands. Since the images are then cemented 
together face-to-face, no emulsion surface is exposed to the wear of 
the projector. 

For color films^^ made by stenciling dye solutions on black and 
white positive prints, the stencils are cut by hand with an electrically 
operated needle cutter. Usually six stencils are necessary for each 
copy, and the most expert workers can only cut three feet of stencil 
per hour. After cutting, the gelatin is removed from the stencil by 
means of a solution of sodium hypochlorite. A special coloring 
machine is employed for placing the dye on the film. 

Low cost of productions*^ is claimed for a European development 
known as the "polychromide" process, a four-color subtractive system 
involving the use of double coated film stock. Red, yellow, green, 
and blue-violet dyes are employed. In the Daponte^^ method of 
producing color motion pictures a split beam camera with two lenses 
is used for taking the picture and a two-color additive process em- 

15 Die Photographische Industrie, June, 30, 1924, p. 543. 
1^ Kinematographic Weekly, September 4, 1924, p. 82. 

17 British Jour. Col. Sup., November 7, 1924, p. 42. 

18 British Jour. Col. Sup., July 4, 1924 and March 6, 1925, pp. 27 and 10. 
" Photographic Journal, March 1925, p. 121. 

20 Kinematograph Year Book, 1924, p. 214. 

21 Cinematographie frangaise, April 11, 1925, p. 16. 

Report of the Progress Committee 1924-^5 21 

A German writer^^ remarks that the successful effects achieved by 
the two-color additive motion pictures cannot be accounted for 
solely on the basis of physics, but are believed to be largely due to 
physiological and subjective effects in the observer. This is also 
beheved to be true in the two-color subtractive process. 

A news note indicates that roll film^^ and film pack coated with 
a three-color screen and suitable for color photography will soon be 
available on the market. 

It is also reported that Agfa^^ motion picture film having the 
same emulsion as screen plates for color pictures will shortly be 
placed on the market. 

Interesting features of color photography patents are discussed 
in our Transactions. ^^ 

Films and Emulsions 

As an improvement in the reversal process^*' for the reproduction 
of black and white copy containing no half-tones, the procedure of 
making a print on paper and developing it into a negative is proposed. 
At this stage it may or may not be fixed, after which it is thoroughly 
washed and dried. India ink is applied with a tuft of cotton to the 
entire gelatin surface. The print is then treated with a solution of 
hydrogen peroxide and nitric acid. Washing in water removes the 
attached gelatin and leaves a black and white positive print in carbon 
pigment. In another process^^ the film is developed in amidol and 
then bleached to chloride. After washing the film is exposed and 
redeveloped. Reversal depends on the difference in sensitiveness of 
the bromide and reformed chloride, which is affected by the washing 
after bleaching. A third process^^ uses a solution of sodium bisulfite 
and sodium hydrosulfite for the redeveloper after re-exposure. It is 
claimed that the harmful effect of alternate immersion in alkaline 
and acidic solutions is avoided, and the second development can take 
place by chemical action alone without exposure to fight. A fourth 
method^^ is based on a combination of the bromoil and pinatype 

22 Kinotechnik, December 10, 1924, p. 441. 

23 Die Photographische Industrie, Oct. 27, 1924, p. 951. 

24 Camera (Luzern), April 1925, p. 231. 

25 Trans. S.M.P.E., No. 21, 1925, p. 113. 

26 Atelier, March 1925, p. 23 

27 II. Prog.fot., April 1925, p. 121. 

28 British Jour., May 9, 1924, p. 280. 

29 British Jour., May 9, 1924, p. 276. 

22 Transactions of S.M.P.E., January 1926 

processes. A very clear image must be obtained by short exposure and 
development in an acid amidol solution. (Process apparently the 
same as Kodachrome except slight difference in composition of 
bleach bath.) 

Basing his conclusions^ ° on a large mass of experimental evidence 
which he presents, a German writer delimits three types of processes 
for the reversal of film negatives. The Luppo-Cramer solarization 
hypothesis is rejected, and the mechanisms of the Villard and 
Herschel effects are discussed in detail. For motion picture pho- 
tography^^ by amateurs a German firm uses the same scheme em- 
ployed in this country of finishing the film after exposure and returning 
it to the amateur ready for projection. 

To avoid the difficulties with reversal processes^^ now employed, 
a process is suggested involving the use of a special bleach bath to 
convert the first image into a modification of silver chloride which is 
not light sensitive. This acts as a negative for the second exposure. 
The time of washing after bleaching controls the sensitivity and 
contrast of the residual silver bromide and after the second exposure 
the reversed image is developed in a suitable developer and fixed, 
giving a silver image. 

Forch^^ found that the inflammability of motion picture film as 
ordinarily finished for projection is increased by the presence of 
silver, whereas a similar film supporting a dye image ignites much 
less readily. In a discussion^^ of the patented processes for eliminating 
scratches on motion picture film, a German author considers the 
best method to be the production of a matte effect on the back of the 
film or the application of a coating of matte lacquer. For the mark- 
ing35 of film, the characters are first written on paper with a special 
acacia ink and the ink sprinkled with a black powder before drying. 

An instruments^ has been devised for measuring the size of 
particles in a medium of specific gravity greater than that of the 
particles measured. The apparatus is of the U-tube tj^pe and is 
modified in that the capillary side arm is connected to the sedimenta- 
tion tube near the top. 

30 Zeitschrift Physikalische Chemie, January 20, 1925, p. 337. 
3^ Phoographische Korrespondenz, December 1924, p. 9. 

32 Die Photographische Industrie, January 26, 1925, p. 83. 

33 Die Photographische Industrie, October 31, 1923, p. 549. 

34 Kinotechnik, January 15, 1924, p. 7. 

' 35 Amer. Jour, of Roentgenology, October 1924, p. 390. 
36 j,Amer. Chem. Soc, December 1924, p. 2709. 

Report of the Progress Committee 19^4-^5 23 

A study^^ has been made of the so-called "deterioration fog" 
which is found in emulsions kept for variable periods without exposure 
to light. Using definite conditions of development, an experimental 
emulsion showed an initial fog density of 0.09 which increased in one 
month to 0.5. Measurements of developabihty of emulsions recoated 
in one-grain-layers were also made. The percentage of grains fogged 
seems to follow an equation similar to Silberstein's equation of photo- 
graphic exposure. Another instruments^ has been developed for 
measuring the swelling of gelatin on rigid supports. 

Comprehensive discussions of film handhng at high tempera- 
ture,^^ reducing the appearance of graininess/° and static markings,^^ 
appear in our Transactions. 


A recently expressed EngHsh opinion'^^ of the ideal motion 
picture film is that it should be a so-called speaking film, free from 
rain and flicker effects, in natural colors and projected stereoscopi- 
cally. It is predicted that the perfection of a continuous projector 
will eliminate the flicker effects, and it is expected that the other 
developments under way will bring this ideal motion picture into 
use before the Utopias are reached in other fields. 

An effort^s has been made in England to form a technical society 
for projectionists. The aims of the technical society are radically 
different from those of the projectionists' trade unions, so that their 
activities should not overlap with resulting delay in the formation 
of the new society. 

Although it is stated that the details in part are being held as 
military secrets, it is of interest^ to learn that some work has been 
done with the photography of objects concealed by water vapor in 
the form of natural fogs and cloud banks. It is expected that the 
present developments will be perfected to a great extent. The results 
depend principally on the use of photographic emulsions sensitive 
to radiation outside of the visible spectrum. 

37 pjiot. J., March 1925, p. 134. 

38 /. Opt. Soc. Amer., August, 1924, p. 181. 

39 Trans. S.M.P.E., No. 19, 1924, p. 39. 

40 Trans. S.M.P.E., No. 19, 1924, p. 49. 

41 Trans. S.M.P.E., No. 21, 1925, p. 67. 

42 British Jour., July 3, 1925, p. 398. 

43 Kinematograph Year Book, 1924, p. 216. 

44 Christian Science Monitor, December 27, 1924. 

24 Transactions of S.M.P.E., January 

The observation of motion^^ as dependent on the functioning of 
the human eye and its application to the motion picture problems 
have been studied by a German writer. 

As a convenience^^ for the patrons an electrically lighted indicator 
is proposed to show the number of reels in the show and the particular 
one showing at the time. This indicator is mounted over the ticket 

The series of articles^'' on light projection, to which attention was 
called in last year's report, have been continued during the past 
year and are well worth reading by all interested in light projection. 

The City of Cleveland is considering a plan^^ for the establish- 
ment of motion picture centers for children to provide wholesome 
entertainment for children at nominal rates. The performances 
would be given on Saturday afternoon. Another plan is to operate 
motion pictures during the noonday program in high schools for 
children who cannot go home to lunch. It is suggested that an admis- 
sion charge of 2 cents be asked for these programs. 

Proper shielding of the cooling plate and light source are recom- 
mended^^ as necessary to the preservation of the eyesight of the 

Although America leads the world, Germany leads other Euro- 
pean countries in the production of new pictures. ^° 


Progress with arc lamps^^ has largely taken the form of perfection 
of mechanical detail on existing equipments rather than of modifica- 
tion in the principles of design or operation. For very large theatres 
a high intensity arc lamp of English manufacture employs specially 
cored carbons, but unlike the American lamps the positive carbon 
is not rotated. Even crater-burning is controlled by an adjustable 
system of lamp-house ventilation. 

The use of the incandescent lamp^^ ^^g g^ light source is discussed 

4^ Kinotechnik, December 25, 1924, p. 469. 

46 Exhibitors Herald Sup., March 28, 1925, p. 20. 

47 General Electric Review, 1924-1925. 

48 Mot. Pict. News, December 27, 1924, p. 3284. 

49 Trans. S.M.P.E., No. 20, 1924, p. 20. 
so Trans. S.M.P.E., No. 19, 1924, p. 23. 
^^ Kinematograph Year Book, 1924, p. 213. 

52 Die Photographische Industrie, Sept. 8, 15, 22, and 29, 1924, pp. 795, 
825,-849, 876. 

i^moiec/iniA;, July 25, 1924, p. 228. 

Report of the Progress Committee 1924-25 25 

in considerable detail by a German writer, with data on projection 
lamps and the efficiencies of different projecting systems and con- 
densing lenses. Apparatus for both still and motion pictures is 

A detailed description^^ of the manufacture of tungsten filament 
lamps for motion picture projection presented at the Schenectady 
meeting includes some of the manufacturing variables affecting lamp 

Laboratory Practice and Apparatus 

In a device^^ for periodically washing or changing the water in a 
film washing tank, a syphon is used which is automatically started 
and broken at proper intervals by a venturi constriction on the feed 
water line. The action of the constriction is regulated by the rise and 
fall of water level in relation to an inverted bell which forms its air 

Iron toning^^ is suggested for a hard negative to make it yield 
softer results. 

A motion picture camera^^ can be used as a printer by the removal 
of the lens and making a light tight connection from the opening to a 
lamp-house. An auxiliary film magazine is used for the negative 
film, and the positive is threaded in the camera through the regular 
feed magazine. Both films are in contact in the gate and are allowed 
to run into an extra box under the camera. 

A new desensitizer^^ known as "Pinakryptol Green Th.," has 
been found which, although it is a derivative of pinakryptol green, 
is 40 times as powerful when used in the same concentration. One 
gram dissolved in 100 liters of water desensitizes so thoroughly that 
a plate may be developed in bright yellow light. 

Among the new equipments'^ introduced in France is a semi- 
automatic electrically actuated step printer. Notches in the edge 
of the negative actuate the light change, and the particular exposure 
is controlled by a punched paper tape resembling a piano player 

53 Trans. S.M.P.E., No. 21, 1925, p. 90. 
5* Phot. J., January 1925, p. 34. 

55 Amer. Phot, March 1925, p. 154. 
British Jour., May 8, 1925, p. 274. 

56 Amat. Phot, May 13, 1925, p. 488. 

5^ Photographische Korrespondenz, April 1925, p. 4. 
58 Sci. Ind. Phot, December 1923, p. 133. 

26 Transactions of S.M.P.E., January 1926 

record. A sampling machine for negatives makes at one exposure 
frames varying in intensity to correspond with densities produced 
by the printer, and a new title making outfit with an hourly capacity 
of three thousand feet uses transparencies with black print for titles. 
Data covering investigations of photographic developers^^ and 
an improved sector wheel for Hurter and Driffield sensitometry^° 
appeared in our Transactions. 


A new projection lens^^ of English manufacture is claimed to have 
very high illumination efficiency and is so designed that it is not 
necessary to move the lens forward and backward when the projector 
has a front threading gate. Marginal definition is said to be as good 
as at the center of the field. Projector lenses^^ of large aperture are 
recommended for use with mirror arcs in conjunction with a single 
condenser lens. 

A German f /2 lens^^ possesses at full aperture very high speed, but 
at smaller apertures is slower and has lower brilliancy than other types. 

A new condenser^^ for arc lamps of foreign manufacture consists 
of two front plano-convex lenses and two rear strongly curved 
meniscus lenses. All except the last front component are of nearly 
colorless fireproof glass which permits the condenser to be brought to 
about one inch from the arc crater with a resulting increase in light 
efficiency due to the increased collecting angle subtended by the lens. 

The manufacture^^ of curved surfaces other than spherical, with 
special reference to the use of spherical tools, has been published as 
part of a "Cinematographic Study of the Working of Optical Sur- 
faces." Suggestions for practical tests of projection lenses were 
presented at the Chicago meeting. ^^ 

Lighting Equipment 
Some of the producing companies" carry powerful and elaborate 
equipment for the production -of desired lighting effects, no matter 

59 Trans. S.M.P.E., No. 19, 1924, p. 28. 

60 Trans. S.M.P.E., No. 21, 1925, p. 85. 

6^ Kinematographic Weekly Sup., December 11, 1924, p. 78. 

62 Kinotechnik, August 25, 1924, p. 269. 

63 Kinematographic Weekly, July 24, 1924, p. 80. 

64 Kinematographic Weekly, February 28, 1925, p. 82. 

65 Rev. d'Opt., July 1924, p. 334. 

66 Trans. S.M.P.E., No. 20, 1924, p. 75. 

■ ' ^' Mov. Pict. World, June 6, 1925, p. 681. 

Report of the Progress Committee 1924-25 27 

where the pictures are to be taken. One company boasts of two 
1600-ampere portable generators, one of 800-ampere and another of 
400-ampere rating, in addition to a 300-kilowatt generator mounted 
on a trailer. All of these units are equipped with their own engines. 
The lighting equipment includes two 30-inch arc searchlights, several 
of smaller size, 15 high intensity arc spotlights, 50 smaller spot lights, 
and 150 side lighting units. If used at one time these equipments 
could furnish an enormous amount of light for almost any location 
and almost literally turn night into day. 


Successful motion pictures^ ^ of microscopical objects are only 
possible if the camera and microscope are separated so that vibrations 
of the former are not transmitted to the latter and if the field can be 
observed during the process. This is possible by means of the Gold- 
berg microscope attachment, which contains a semi-transparent 
mirror that reflects part of the light perpendicularly into the camera. 
The movement of the object can be observed during the operation, 
and consequently it can be maintained in focus. Sharp pictures may 
be obtained at distances from 7 to 80 cm. 


Of especial interest in connection with the inventions'^ of devices 
to produce cold light which appear from time to time is the complete 
classification of various types of luminescence which appears in a 
recent publication. Each type is clearly defined. It is of interest to 
note that the efficiency of the firefly^" as a producer of cold light may 
not be as high as is ordinarily supposed on account of the lack of 
measurement of non-radiated heat. The light efficiency of phosphorus 
is only about one-thousandth that of the Mazda lamp. 

For the determination of the percentages of light reflected by 
surfaces, a new reflectometer has been developed which is simple in 
construction yet has good accuracy. '^^ 

68 Kinotechnik, September 25, 1924, p. 320. 

69 Gen. Elec. Rev., February 1925, p. 103. 
^0 Trans. I.E.S., April 1925, p. 392. 

^1 Trans. S.M.P.E., No. 21, 1925, p. 101. 

28 Transactions of S.M.P.E., January 1926 


A continuous projector ^^ Qf German manufacture (Leitz) employs 
a complex lens system in which the light passes through six lenses 
and is reflected four times before being sent toward the screen. The 
resulting light loss is estimated at 50 per cent. From the condensing 
lens light passes to rotating and oscillating mirrors, a total reflection 
prism, into the projection lens, to another rotating and oscillating 
mirror, the second projection lens, mirror, and then to the screen. 
It is reported that the projection is bright, crisp, and steady, and the 
machine can be run at speeds above normal or at two or three pictures 
a second only. It appears to be a marked scientific advance but has 
two drawbacks: (1) The first cost is high, and (2) the wearing 
qualities are still undetermined. 

Another optical system ^^ for continuous projection utilizes an 
optically correct glass ring on whose inner periphery are a number of 
lenses, the whole rotating around the ring center, which is the 
common focus of all the lenses. Projection speeds as low as three 
pictures a second are stated to be satisfactory. Still another con- 
tinuous projector ^^ which carries up to 5,000 feet of either standard 
or narrow width film is similar in appearance to a standard phono- 
graph. A continuous film movement ^^ is used on a projector produced 
in Germany for advertising purposes in show windows. It is entirely 
automatic in operation. 

An English projector^^ recently introduced has a horizontal film 
box and automatic rewind, which uses a large diameter central hub, 
and a split spool in the lower film box. For re-projection the outer 
half of the spool is unlocked, placed in the upper horizontal film box, 
and the film threaded through a curved track protruding from the 
box. The shutter sends a current of air to the film. 

At the Leipzig Spring Conventions^ held in 1923, the A. E.G. new 
model projector shown was fitted with a device for projecting still 

^2 Kinematographic Weekly, September 4, 1924, p. 78. 

Kinematograph Year Book, 1924, p. 212. 
^3 Die Photographische Industrie, August 22, 1923, p. 419. 

74 Mot. Pict. News., February 23, 1924, p. 898. 

75 Kinotechnik, February 25, 1925, p. 84. 

76 Kinematographic Weekly, June 26, 1924, p. 64. 
Kinematograph Year Book, 1924, p. 211. 

77 Die Photographische Industrie, March 21, 1923, p. 136, 

Report of the Progress Committee 19^4-^5 29 

pictures. A shutter placed in front of the film gate both absorbs heat 
and generates a blast of air for cooling the gate. 

Various methods^^ have been employed for reducing the heat 
in the hght beam or rapidly cooling the film in mirror arc projectors. 
For both cooling the beam and concentrating light to the film gate, 
an optical device has been devised which fits on the lamp-house. 
A brass cylinder carries a negative concave lens and a large diameter 
positive convex lens; the combination produces a slightly negative 
value. About 2 per cent loss of light and 50 per cent heat reduction 
are claimed, although the first figure is obviously incorrect. 

For the cooling^^ of film by the use of an air-blast, one system 
takes air directly from the projection room', while the other uses 
moistened air. The data showed that the film life was nearly doubled 
when using moistened air. The use of a cooling celP° containing a 
solution of copper sulfate is criticized on the basis that the efficiency 
of the lamp is decreased by 40 per cent. The air ventilating shutter 
scheme is recommended, since it is said to decrease the heat by 
50 per cent without affecting the light intensity. Another writer 
discusses the absorption of heat^^ by photographic silver density and 
presents measurements obtained to show the effect of certain liquids 
intended to absorb the heat in a projection system. Temperature 
data^2 have been obtained in Germany for ordinary and reflector arcs 
for film cooled by compressed air. 

Exception is taken to Flinker's data^^ on the shrinkage of motion 
picture film exposed to an air blast; the point is made that if the life 
of a film is assumed to be 500 projections, the total exposure time 
would be considerably less than that required to cause a shrinkage of 
1 per cent, which is considered the practical limit. 

As a speed indicator, ^^ an automobile speedometer has been used 
attached to the projector machine shaft. Another European device ^^ 
stops the projector when the lamp-house is moved to one side by 
opening the motor switch. 

^s Kinematographic Weekly, June 12, 1924, p. 48. 
^» Kinotechnik, May 10, 1925, p. 216. 
^° Kinotechnik, January 15, 1924, p. 13. 

81 Amer. Phot, June 1922, p. 397. 

82 Kinotechnik, May 25, 1924, p. 136. 

83 Kinotechnik, August 10, 1924, p. 258. 

84 Kinematographic Weekly, April 16, 1925, p. 87. 

85 Kinematographic Weekly Sup., April 2, 1925, p. 87. 

30 Transactions of S.M.P.E., January 1926 

In a hotel ballroom ^^ where it was desired to install a motion 
picture projector in such a way that the elaborate furnishings would 
not be interfered with, such as modification in the design of the 
chandeliers on account of interference with the light beam, the 
problem was solved by directing the beam in such a manner that 
it did not strike the chandeliers. This was effected by the use of a 
two-mirror periscope which dropped the beam several feet below 
the level of the projector objective. A tandem condenser system was 
employed with special large diameter objective lenses, incandescent 
lamps being used to project the pictures 145 feet. 

A new lamp unit^^ for theatre projectors uses a relay condenser 
system and incandescent lamps. 

Projection Room Equipment and Practice 

A film inspection machine^^ has a set of fingers and rolls on an 
automatic rewind, so connected with the driving mechanism that a 
poor patch, break in the perforation, or a tear in the film, stops the 

Coating the perforation area^^ of a film with opaque white at the 
change-over point is reported to be a satisfactory method of indicating 
to the projectionist that the end of a reel is approaching. Another 
change-over signaP° suggested to audibly warn the projectionist is 
increase of the film thickness so that it would make a noticeably 
different sound on passing through the projector gate. 

For a film joiner ^^ a glass plate is mounted on a wooden base on 
which half a hack saw blade is mounted. The film is pushed under the 
blade with the free edge projecting from the smooth side. The other 
half of the blade with the edge ground flat is used to scrape the 
emulsion off the film. 

The allotment of adequate funds for the equipment and main- 
tenance of the projection room is strongly recommended as necessary 
to give the patron his due as well as from the standpoint of good 
business. ^2 

^^ Amer. Cinematographer, August 1925, p. 4. 
" Trans. S.M.P.E., No. 20, 1924, p. 82. 

88 Mot. Pict. News, November 22, 1924, p. 2658. 

89 Kinematographic Weekly, September 25, 1924, p. 68. 

90 Kinematographic Weekly Sup., December 11, 1924, p. 76. 

91 Kinematographic Weekly, June 18, 1925, p. 56. 

92 Trans. S.M.P.E., No. 20, 1924, p. 43. 

Report of the Progress Committee 1924-25 ' 31 

Radio Vision 

As a leading editorial writer ^^ states, "radio vision is not an 
impossibility, and it is conceivable that in any home there may be a 
white screen on which will appear a moving picture from any station 
where something of interest is going on." The work of one of our 
members and his recent report of progress^^ in the Transactions 
has been followed with interest by the Society. English^^ and French^^ 
experimenters are also active on the problem. 


An excellent discussion of translucent shutters was presented 
before cur society. ^^ 


It is proposed in Germany that cores^^ in film spools be stan- 
dardized for motion picture cameras with a standard position of the 
film with respect to the emulsion coated side and a standard manner 
of winding raw film by the manufacturers. The disadvantages of 
having to rewind film before putting it in the camera are discussed. 
In another discussion of standardization^^ of film widths, it is pro- 
posed that it would be wise for German manufacturers to adopt the 
16 mm. width for amateur use as has bean done in this country. 

A cinematographer^°° discusses the demand for rapid projection 
by theatre managers, which he states is often 70 feet per minute or 
more, and advocates returning to the standard of 16 pictures per 
second as a means of reducing the loss in torn sprocket holes and 
other film damage. 


Government reports^ °^ show a considerable falling off in film 
imports for 1924 as compared to 1923. While 2,228,660 linear feet of 
negatives valued at $942,807 came into the country in 1924 as 

93 New York Times, March 21, 1925. 
'' Trans. S.M.P.E., No. 21, p. 7. 

95 Christian Science Monitor, December 27, 1924, p. 12. 

96 Christian Science Monitor, December 4, 1924, p. 7. 
" Trans. S.M.P.E., No. 20, 1924, p. 53. 

98 Kinotechnik, December 25, 1924, p. 465. 

99 Die Photographische Industrie, Feb. 2, 1925, p. 127. 
i<"^ Amer. Cinemat., March 1925, p. 7. 

i«i Mot. Pict. News., July 11, 1925, p. 189. 

32 Transactions of S.M.P.E., January 1926 

compared with 2,064,390 valued at $657,509 in 1923, imports of 
positives for 1924 amounted to only 4,502,031 linear feet valued at 
S241,065 in comparison with 7,053,232 linear feet valued at $323,493 
for the previous year. How small a comparative total these f gures 
represent is aptly illustrated by the fact that American exports of 
positives wore in 1924 nearly 180,000,000 feet or approximately 
40 times as great as our imports, while the 8,000,000 feet of negative 
exported in 1924 were nearly four times the amount of negatives 

According to the official German statistics, ^"^ Germany exported 
during 1924, 48 million meters (157 miUion feet) of raw motion 
picture film and 8 million meters (26 million feet) of printed film 
compared with 29 million meters (95 million feet) of raw film and 
13 million meters (42 milHon feet) of printed film exported in 1923. 

There are at present 4500 motion picture theatres^°^ in Germany 
with 1,000,000 seats. Berlin has 300 theatres with a patronage of 
100,000 persons per day. New York is said to have a daily attendance 
of 600,000. World production of motion picture film is given as about 
500 million meters (1 billion, 640 million feet) per year. Germany 
now exports about 80 million meters. 

An analysis^ °^ of accidents in motion picture theatres reveals the 
fact that only 6.3 per cent are a result of fire. 

Stereoscopic Projection 
For the projection^ °^ of stereoscopic pictures a French method 
superimposes two images simultaneously on the screen. A relief 
effect is obtained by means of the so-called disk pulsator. The 
total Hght falling on the screen is constant at all times, but the 
intensity of illumination of the two images is varied in a continuous 
manner by means of a glass disk having dark and light zones. A 
partial stereoscopic effect^ °^ is planned for an English development 
known as the Pulsograph. It operates on the principle of projecting 
pictures alternately from a pair of films. Another process^°'' for 
stereoscopic motion pictures uses only one camera, one projector, 
and a single film. No experimental details are given. 

i°2 Science, Ind. Phot., January 1925, p. 7. 

103 Die Photographische Industrie, Feb. 23, 1925, p. 184. 

"'^ Mot. Pict. News, March 7, 1925, p. 1031. 

lo^ Cinematographie franqaise^ March 7, 1925, p. 14. 

1"^ Kinematograph Year Book, 1924, p. 215. 

1"^ Kinematographic Weekly Sup., January 22, 1925, p. 81. 

Report of the Progress Committee 192^-25 33 

Studio Lighting 

In discussing the illumination^^^ of motion picture studios a report 
prepared by the Societe Fran^aise des Electriciens covers both the 
photographic requirements and the physiological effects on the skin 
and eyes. Since the effects on the skin may be remedied by the 
use of grease pamt or other preparations, the report emphasizes 
particularly the effect on the eye. Two suggestions are made to 
diminish the harmful effects: (1) As much as possible of the pre- 
liminary work should be done in subdued light, thus exposing the 
eyes only while the film is being exposed; (2) Diffusing material 
should be placed between the actors and the light source or glass to 
absorb the ultra-violet rays. The author concludes that the final 
solution lies in the use of panchromatic negative film which will 
obviate the use of light sources harmful to the eye. 

The use of a blue filter^°^ for examination of the lighting quality 
of a studio setting is proposed. Blue bulb photographic incandescent 
lamps are recommended for "bank" lighting effects to supplement 
daylight. Yellow tinted screens are useful in portraiture when an 
enclosed arc is employed which tends to give distinctly violet light. 

Where electricity^^ ° is not available, as on distant locations, 
magnesium candles can be used as light sources. The need for protect- 
ing the eyes against strong violet light is discussed. 

Studio Effects and Practice 

In order to produce the illusion^^^ of ghosts or similar phantoms 
floating upward or in any direction in the air, the objective of the 
motion picture camera is slowly moved in any desired direction by a 
device fastened to the top of the camera. 

In a recent motion picture film^^^ certain very busy sections of 
Paris were represented without vehicles or pedestrians. This effect 
was achieved by the use of an old device which consists of using very 
long exposures by means of a slow emulsion, a small diaphragm open- 
ing and a very dense colored filter. Under these conditions each 
passing object crosses the field for only a minute fraction of the 
total exposure and does not affect the register of fixed objects. 

"8 Sci. Ind. Phot, February 1924, p. 17. 

109 British Jour., May 15, 1925, p. 286. 

11° Die Photographische Industrie, March 9, 1925, p. 282. 

111 Kinotechnik, January 10, 1925, p. 18. 

112 Sci. Ind. Phot., January 1925, p. 11. 

34 Transactions of S.M.P.E., January 1926 

Soft focus effects^^^ have been obtained by the use of veilings to 
cover part of the opening of the rotating shutter of a motion picture 
camera, thus giving the film a sharp image for part of the exposure 
and a soft image for the remainder. Different effects may be obtained 
by choosing fine or coarse veilings or veilings of different color or by 
changing the ratio of the veiled opening to free openings. 

Suggestions are given for the use of make-up under various 
lighting conditions^^^ and a few of the standard methods of securing 
trick effects are briefly described in recent publi cations. ^^^ 

Natural effects are obtained^^^ by the artistic utilization of 
light, with judicious placing of spot and flood units. 

Super-Speed Motion Pictures 

A French inventor^^^ demonstrated in England last year motion 
pictures taken at speeds varying between 2,000 and 30,000 pictures 
a second. For the highest taking speeds the film band was held 
stationary and the image caused to traverse it by the rotation of a 
prism placed in the optical path of the light beam. The illumination 
was furnished by electric spark, the frequency being controlled by 
charge and discharge of large fixed condensers across a spark-gap. 
In this way records were successfully taken showing bullets propelled 
by high-explosives leaving the barrels of guns and penetrating 
various substances. 

K. Gordon and G. Gimber gave two lectures^^^ on slow motion 
cinematography before the Royal Photographic Society in which 
the relative merits and mechanisms of the Debrie, Pathe, and 
Cinechrome ultra-rapid cameras were discussed, as werie experiments 
in connection with slow motion as carried out in the Gaumont Labora- 
tory by the latter speaker. 

Talking Pictures 

For the recording^^^ and reproducing of sound in a German 
development, the microphone current is amplified and caused to vary 
the intensity of a glow lamp similar to a Geisler tube which exposes 

"3 Kinotechnik, February 25, 1925, p. 77. 

"^ Kinematographic Weekly Sup., January 29, 1925, p. 88. 

115 Phot. J., January 1925, p. 36. 

116 Trans. S.M.P.E., No. 21, 1925, p. 21. 
11''' Kinematograph Year Book, 1924, p. 216. 

11^ Kinematographic Weekly, June 12, 1924, p. 55. 
. ' 119 Kinotechnik, December 1922, p. 857. 

Report of the Progress Committee 1924-25 35 

a narrow band at the edge of the film. The sound is reproduced by 
transmitting the variations in Hght from this band to a photo-electric 
cell, which in turn operates a loud speaker. The same general prin- 
ciples^2° appear to be used in another device for reproducing sound 
from a film record in which a photo-electric cell and an electrostatic 
telephone are employed. 

A German writer^^i points out that when heard with both ears, 
it is possible to determine the direction of a sound to within 3 per cent, 
which makes it difficult to produce the illusion of sound coming from 
a single character on the motion picture screen. The desirability of 
having a stereoscopic arrangement for recording and reproducing 
sound is proposed. 

Improvements in the Phonofilm apparatus were descibed before 
our Society at the Chicago meeting. ^^2 

Theatre Practice and Effects 

It has been pointed out that the colored lighting effects^^s pj.Q_ 
duced by the Clavilux are not intended to suggest anything other 
than their own intrinsic beauty. While they have been largely used 
as solo features, they can be employed for the production of sub- 
ordinate lighting effects synchronized with the music and other 
action. It has also been used for the decoration of the picture title 
and sub-titles, both in monochromes and color. The projection of 
mobile and static settings for dramas, dances, pantomine, and ballets 
are other applications. It is predicted that soon the electrician must 
evolve into an artist on a par with the organist. 

A German director^^* proposes for the sake of conveni3nce and 
saving of time in orchestra rehearsals and for the adapting of music 
to film plays that a device be employed by means of which the 
orchestra leader may reverse or accelerate the film to repeat certain 
scenes at will. He also proposes a device to register ''film seconds" 
which shall be visible to the leader and a device whereby the leader 
may retard or accelerate the film within limits. 

120 Mot. Pict. News, Sept. 5, 1925, p. 106. 

Die Photographische Industrie, Nov. 15, 1922, p. 945. 
Amer. Cinematographer, August 1925, p. 9. 

121 Kinotechnik, December 1922, p. 862. 

122 Trans. S.M.P.E., No. 20, 1924, p. 17. 

123 MoL Pict. News, May 30. 1925, p. 2699. 

124 Kinotechnik, December 10, 1924, p. 442. 

36 Transactions of S.M.P.E., Januanj 1926 

Basing his opinions on experiences^^^ as a solo rehearser for the 
Dresden Opera, another conductor emphasizes the necessity for 
close co-operation between the illuminating engineer and the musical 
stage manager. A color music pianoforte recital is suggested. 

The importance of co-ordinating the lighting effect^^^ with the 
performance has been given especial attention by the managers of 
our outstanding theatres. At one large house a lighting rehearsal 
is used to work out the details of the lighting effect. 

A curtain draw^^^ which can be controlled from remote places 
has been recently introduced. The equipment is motor driven and 
by the judicious use of leather and wood in combination with the 
metal parts practically noiseless operation is secured. Control may 
be effected from as many places as is desired. 

Flexible and complete control in addition to adequate lighting 
equipment form the basis of effective theatre lighting. ^^^ Proper 
combination of temperature and quantity for the air are necessary 
in theatre ventilation. ^^^ 

Colored lighting effects have been emplo3^ed with marked 
success^^° to supplement the picture projection, and offer many 
possibilities for the embellishment of the program. 

Visual Education 

In the educational field^^^ considerable stress has been laid on the 
ability to teach certain subjects by motion pictures with better 
results than where the ordinary forms of instruction are employed. 
Some studies and experiments^^^ have been made showing that motion 
pictures offer promise of effecting a material saving in time in that 
branch of education which consists in imparting information. From 
40 to 623^^ per cent saving in time was effected where the motion 
picture used was well constructed and adapted to the purpose. 

The general acceptance of educational motion pictures^^^ is 
progressing slowly in England, but it is encouraging to note that the 

125 The Illuminating Eng., October-December 1924, p. 160. 

126 Mot. Pict. World, April 4, 1925, p. 6450. 

127 Mov. Pict. World, May 16, 1925, p. 321. 

128 Trans. S.M.P.E., No. 20, 1924, p. 23. 

129 Trans. S.M.P.E., No. 21, 1925, p. 13. 

130 Trans. S.M.P.E., No. 21, 1925, p. 38. 

131 Trans. S.M.P.E., No. 20, 1924, p. 65. 

, 132 The Educational Screen, January 1925, p. 13. 
133 Kinematograph Year Book, 1924, p. 217. 

Report oj the Progress Committee 192 1^.-25 37 

government recently appointed a committee of educators to deter- 
mine the value of the motion picture in education which rendered a 
very favorable report to the effect that it did not impart instruction 
in a shallow way as many thought, so that the lesson was soon for- 
gotten, and that instead of stinting the students' powers of imagina- 
tion it helped to develop them. 

The U. S. Department of the Interior^^^ in a recent bulletin 
states that a large number of state institutions and those of larger 
cities regard visual education as of sufficient importance to warrant 
its organization into distinct departments. In Germany^^^ as well 
this subject is receiving considerable attention. A number of articles 
have appeared discussing different phases of this subject. In the 
technical high schooP^^ at Charlottenburg and at the Munich "film- 
schule" motion picture photography and projection are taught. The 
latter school is supported by the Bavarian government and gives a 
two-year course in cinematography. During the first year the 
student is instructed in the theory and practice of general photog- 
raphy. During the second year, attention is given to the study of the 
theory of motion picture photography, film finishing, and projection. 

A new handbook^^'' on visual education discusses the sources of 
supply for the materials of visual education, includes a bibliography 
of the subject, and among several articles of interest includes one of 
particular value entitled "The Place of Motion Pictures in Educa- 
tion." Articles pubhshed on the fundamentals of graphing^^^ give 
interesting data for students of visual education. 

X-ray Motion Pictures 

X-ray pictures^^^ of the heart were taken by photographing the 
image formed by X-rays on a calcium tungstate screen. Seventeen 
pictures per second were obtained with the X-ray tube operating 
at 80 kilovolts and 200 milliamperes. A lens of quartz and uviol 
glass was used, of aperture f/1.55. 

134 Bulletin No. 8, Dept. of the Interior, Washington, D.C., 1924. 
^^ Die Photographische Industrie, November 10, 1924, p. 1023. 

Die Photographische Industrie, December 8, 1924, p. 1135. 

Visual Education, December 1924, p. 446. 

Educational Screen, January 1925, p. 9. 
13^ Kinotechnisches Jahrbuch, 1922-23, p. 16. 

13^ Visual Instruction Handbook of Visual Instruction Association of Amer., 
New York City, June 1924. 

138 Visual Education, July 1924, p. 190 and August 1924, p. 238. 

139 Bulletin des Rehcerches et des Inventions, June 15, 1924, p. 581. 

38 Transactions of SM.P.E., January 1926 


Mk. Ives: There was a reference in the paper to making two- 
color films cemented face to face. I suppose it would not be improper 
for me to say that I patented this idea so many years ago that I have 
forgotten the date. (U. S. Patent 1,248,864, December 4, 1917, 
application filed February 4, 1916.) 




This paper describes a special lamp base and a special socket for 
projection lamps. The lamp filament position is set accurately at the 
basing operation, so that lamps are interchangeable without socket 
adjustment in projection equipment. 

PROJECTION equipment usually requires that the light source 
be placed accurately at the correct operating point on the opti- 
cal axis. To accomplish this with incandescent lamps using 
the standard Edison medium screw base, special adjustment of the 
mirror, if used, and of the socket must be made for each lamp. 
Often, even when provision has been made for socket and mirror 

Fig. 1 

adjustment, no attempt is made to align the filament due either to 
inexperience on the part of the user or the difficulty of adjusting a 
hot lamp. The ideal situation from the viewpoint of the user of the 
equipment would be a condition where lamp and mirror adjustments 
are unnecessary. 

The requirements (see Fig. 1) for a set up to meet this ideal 
condition are: 

(1) Accurate lamp light center 

* Edison Lamp Works of General Electric Co., Harrison, New Jersey. 


40 Transactions of S.M.P.E., January 1926 

(2) Accurate axial alignment of filament and base 

(3) Positive location of filament plane 

(4) Correctly aligned socket 

(5) Correctly aligned mirror 

The standard Edison base does not meet these requirements 
for several reasons: First, because it is practically impossible to 
manufacture large lamps and to base them with the required accuracy. 
Second, because with a threaded base, the filament plane cannot be 
positively predetermined with reference to the socket. 


Fig. 2. Prefociising Base 

A. Inner Shell 

B. Outer Shell 

To meet these requirements a new base and socket have been 
designed. The base consists of two shells (see Fig. 2), one of which, 
shell A^ is attached to the lamp seal in the usual manner. This 
shell fits in the outer flanged shell B and may be moved in and out, 
rotated, or rocked about the bead of the outer shell to align the fila- 
ment. After alignment the two shells are fastened permanently with 
solder. The outer shell carries two unequal flanges which in connec- 

Prefocusing Base and Socket — Burnap 


tion with the barrel of the shell align the base in the socket and locate 
the filament position accurately. 

The socket (see Fig. 3) is simple and rugged. It consists of a 
shell with engaging ears for the base flanges. The bottom contact is 
pressed against the eyelet of the base and holds the flanges firmly 
against the socket ears. The use of two unequal flanges permits of 
inserting the lamp in only one position in the socket, which is a 
desirable condition for use in optical systems using short focus con- 
densers. The form of the insulation of the shell is unimportant except 

Fig. 3. Prefocusing Socket Construction 

that a true surface must be available for alignment and for attaching 
the socket to the projection equipment. To obtain the maximum 
accuracy, the equipment manufacturer should locate sockets by trial 
and fasten securely in place. 

The handling of this base in the factory is still in the develop- 
ment stage. Fig. 4 shows an experimental model for aligning lamp 
filament and base. In brief, the device consists of a solid socket, an 
adjustable bulb holder, and two lenses which project images of the 
lighted filament to a screen. The bulb is shifted until the image of the 


Transactions of S.M.P.E., January 1926 

top of the filament and the image of the front of the filament fall 
within outlined spaces on the screen. The two base shells are then 
soldered together, thus insuring positive and accurate location of the 
filament with reference to the barrel and flanges of the outer base 

Fig. 4. Filament Aligning Jig 

This method of basing corrects the unavoidable errors of glass 
assembly in lamp manufacture and permits the manufacturer to 
turn out uniform product which will automatically focus correctly. 
Fig. 5 shows an unbased lamp, a lamp with inner base shell, and a 
completed lamp. 

Prefocusing Base and Socket — Burnap 43 

The trend is toward requiring greater accuracy in the location of 
the lamp filament. The prefocused base meets this requirement 
both for the lamp and equipment manufacturers, because the lamp 
manufacturer can reduce his tolerance for the final product without 
increasing loss due to lamp rejections, and because the equipment 
manufacturer can dispense with socket and mirror adjusting devices 
and can guarantee results. Admitting the need for a prefocusing base, 
the design should be such that the base will have universal application 
and be reasonable in cost. 



Fig. 5 

A. Unbased Lamp 

B. Inner Shell Attached 

C. Completed Operation 

Several types of pre-focusing bases are already in use, each 
adapted to the purpose for which it was designed. Other manu- 
facturers are considering pre-focusing bases for their new models. 
With a view to simplification of base types, as now being worked 
out for lamp types, the lamp manufacturers are proposing a universal 
purpose base. There is a danger, of course, that a new base will lead 

44 Transactions of S.M. P. E., January 1926 

to further diversification rather than to the desired standardization 
unless all projection equipment manufacturers approve and use this 
base. This base meets every requirement for filament alignment and 
uses a socket of simple and therefore rugged design. All possible 
adjustments are provided for aligning the filament accurately with 
reference to a sturdy outer base shell. The smooth cylindrical 
surface of the outer base shell forms in connection with the wide 
flanges excellent aligning surfaces for engagement in the socket. 
If it is desired to meet especially accurate focusing requirements 
or conditions of vibration, the socket shell can be split and arranged 
to clamp tightly about the outer base shell, thus making socket and 
lamp rigid. At present it does not seem desirable to try to meet all 
conditions of operation with one socket type. Furthermore, the 
manufacture of these bases follows standard methods and is done 
on automatic machinery, thus keeping the cost low. 


Mr. Ziebarth: This was a very good demonstration. We tried 
to get the lamp manufacturers to make a pre-f ocusing base about two 
years ago, but we failed to get them interested. We have made a 
base of our own, and it would be difficult to change now. We have 
a very satisfactory way of centering the lamp in our Filmo projector, 
which is described in the 1924 Transactions in a paper by J. H. 

Mr. Palmer: Have they made any sockets to handle high 
wattage lamps like a 900-watt lamp for projection machines? 

Mr. Richardson: These are small lamps, that is as far as 
standard projection is concerned. I noticed one of the lamps was 
off center considerably; with the taller lamp would not this error 
be increased? 

Mr. Benford: Practically every one of the lamps is off a little 
to the left; if the paper had been adjusted a little more carefully the 
lamp would not have looked so bad. 

Mr. Burnap: The first question refers, I believe, to the Bell 
and Howell base: It is unfortunate that we are several years late. 
We hope that Bell and Howell can some day see their way to come to 
this socket because it will take a bulb of any size, which the Bell and 
Howell base as now used will not do. 

Prefocusing Base and Socket — Burnap 45 

In connection with high wattage lamps, we have not any more 
than considered the use of a pre-focusing base for high wattage 
lamps because unless bases are made on automatic machinery the 
manufacturing cost is excessive. In order to make bases on automatic 
equipment we must talk in quantities of thousands of bases. We 
are not prepared to do this for large lamps at "the present time, 
but we have considered it and hope soon to add the large wattage 
lamps to this type of focusing base. 

Mr. Porter has just made a comment to me to the effect that 
where large lamps are used, particularly motion picture lamps, the 
projectionists who are the experts on the job should be able to focus 
them with the adjusting mechanism available. 

Mr. Richardson brought up the question of hght center and 
the effect on accuracy. All the lamps for which we plan to use this 
base will be of the same light center as those which we have been 
demonstrating: that is, 2-3/16 inches from filament center to flanges. 
For high wattage lamps, the base will be larger which will insure 
accurate alignment for the longer light center. 

Mr. John Jones: How accurate do you have to position the 
light source in order not to impair the results? 

Mr. Burnap: As the demonstration outfit is set up, due to 
the magnification used, an error of an inch on the screen represents 
less than half a millimeter variation for the filament position. As 
to what limits should be taken, we feel that if we hold the lamp 
within half a millimeter, we shall meet the requirements of every 
one. Actually, at the present time, pre-focused lamps are more 
accurate than the requirement stated. 

Mr. Richardson: If the center of the lamp filament is on the 
optical axis of the system, the falling off of screen illumination 
is progressively tremendous. I did not mean to be harshly critical. 

Mr. Palmer: I should like to emphasize the desirability of 
having these sockets or some similar device for the higher wattage 
lamps, because, regardless of the fact that the lamps are put in by 
experts, it is frequently necessary to change the lamps quickly, 
and if we had such a socket, it would eliminate errors and result in 
much better projection. 

President Jones: One of the questions, I believe, was how 
high a wattage lamp can be used in this base. I believe that has not 
been answered. 

Mr. Burnap: It is standardized up to 660 watts. 


Eeic T. Clarke* 

IN THIS paper I want to discuss some of the problems confronting 
the exhibitor of motion pictures. These problems do not strictly 
concern motion picture engineers, yet it is the business of the 
exhibitor to present to the public the result of your labors. Having 
been connected with the industry less than two years, I feel much 
more free to express opinions now than I shall later when I know 
more about the subject. After all, the membership of this organization 
is composed of men who are each specializing in some particular line 
of the work; the exhibitor has the advantage of a more general, if 
more superficial, view of the art. The subject is almost unlimited 
in its scope. As it would be futile to try to cover it in one paper, 
I shall confine myself to the question with which we are immediately 
concerned. Next year will probably find us working on other prob- 

There is no need to dwell on the influence of motion picture 
entertainment. It is already recognized by the general public that 
motion picture entertainment is one of the most powerful factors in 
our modern life. The influence is far-reaching. Those who object to 
the movies represent a dwindling minority, and even they have to 
recognize that, whether they like it or not, the public is going to 
insist on having motion picture entertainment. In this connection, 
it is interesting to realize that almost all the recent theatre, construc- 
tion has been in the direction of movie houses. Scarcely anyone 
would now think of erecting even a concert hall without equipping 
it for the presentation of motion pictures. 

The type of motion picture performance has developed rapidly, 
for it is only a few years ago that we had the so-called "nickelodeon" 
with the mechanical piano. This soon gave place to the small theatre 
with organ accompaniment. The serious -minded church or concert 
organist was at first inclined to object to what he considered a debase- 
ment of his art; yet, in a remarka;bly short time an entirely new 
organ technique was developed, and it may be of interest to know that 
the school of music of the University of Rochester maintains a 

*' Director, Eastman Theatre, Rochester, New York. 


An Exhibitor^ s Problems in 1925 — Clarke 47 

department for special instruction in the art of motion picture 
accompaniment. In the next stage came the motion picture house 
with orchestra. Here again the first class musician was at first un- 
willing to engage in the work, and not without justification, considering 
the manner in which the average movie conductor butchered classical 
music. This difficulty has already been largely overcome, and we, in 
Rochester at least, find very little trouble in recruiting the best 
available talent for our theatre orchestra. At the moment we are 
engaged in pointing out to serious-minded American composers the 
almost virgin field of composition for the accompaniment of motion 
pictures, and it is already safe to prophesy that the most lofty- 
minded composers for orchestra will be interested in writing suitable 
scores for use in accompanying motion pictures. 

More recently there has arisen the large motion picture house 
elaborately equipped for the presentation of the so-called "de luxe" 
performance with a big symphony orchestra and in addition short 
stage presentations. The question naturally follows, "What will 
be the next type of what we might call 'super-de luxe' motion 
picture entertainment?" Frankly, I do not know, and there is 
perhaps little need for speculation on this head, since there lies before 
us at this moment ample opportunity for the further development 
in our effort to arrive at the ideal de luxe performance. At all 
events, the de luxe performance is a young child growing rapidly and 
has a big future before it. Those who, like us, are responsible for its 
development have very little precedent to serve as a guide, but we 
have almost unlimited space in which to spread ourselves. Of course, 
there will doubtless be all kinds of motion picture shows, varying 
from the small-town and fourth-run neighborhood house, up to the 
elaborate downtown house, presenting a diversified program. It is 
the de luxe program that I wish to discuss in this paper. 

At the Eastman Theatre in Rochester we must play every week 
to at least one -eighth of the population if we do not wish to lose 
money. Let us begin therefore by considering the type of audience 
which we wish to attract. It is safe to assume that most old-time 
theatre patrons are movie-goers. We find also that the concert-going 
pubHc is being attracted by de luxe shows. This is the so-called "high- 
brow" class which we cannot ignore if we want one-eighth of the 
population every week. The vaudeville-goer is also a movie-goer. 
The gradual tendency toward the inclusion of films in vaudeville 
performances springs from many causes, but it proves that vaudeville- 

48 Transactions of S.M.P.E., January 1926 

goers like films. The de luxe house, in short, is really welding a new 
audience out of all the groups and classifications of the public. 
Play-goers, concert-goers, and vaudeville patrons are only three out 
of the number of classifications which might be made, but they 
will serve to make clear that individual preferences must be satisfied 
if we wish to attract all these people to our house. In the first place, 
it is clear that they form a high-class audience. We have found it 
perfectly safe to equip the house with unusually beautiful and 
expensive appointments. It is a discriminating audience that dis- 
tinctly prefers real quality to tawdry allurements. The most success- 
ful features are never morally questionable. Our biggest success at 
the Eastman Theatre has been Harold Lloyd in "The Freshman," 
and a survey of the twelve most successful pictures of the past season 
contains only one picture which parents might possibly have objected 
to their children seeing. That picture came twelfth on the list. 
Pictures with a strong sex appeal may succeed in other types of 
houses, but I know for certain that they can never beat the attend- 
ance records in a de luxe house. This audience, moreover, is not to 
be attracted by circus methods. Unlike the Broadway houses in 
New York, we, at the Eastman, must keep on appealing to the same 
audience week after week, and it does not pay to attract our audience 
by sensational means. This is a matter which it will be well for 
distributors to consider in producing their illustrated advertising 
sheets. As I hope to point out later, producers have in general shown 
a high degree of artistry and enterprise. Exhibitors are more and 
more becoming interested in high class presentations. The distributor 
who comes in between has been lagging behind, content with pro- 
ducing a type of advertising which is really aimed at the exhibitor 
buying the pictures. It should not be used for attracting a high 
class audience. We find it necessary to maintain our own staff of 
poster men. The posters now produced in quantity may be successful 
for certain classes of houses, but at best they convey an entirely 
false impression of the artistry and photographic beauty contained 
in the feature film. The cause of this condition is, as I see it, two-fold; 
firstly, the distributor is not really in touch with the public, the 
contact is via the exhibitor; secondly, people of artistic appreciation 
engaging in the motion picture industry are more to be found in the 
producing end than in the distributing end. To appeal to one-eighth 
of the population in a city where other forms of entertainment are 
available calls for a diversification of program that will contain 

An Exhibitor^ s Problems in 1925 — Clarke 49 

something to appeal to the particular tastes of the classifications I 
named above. The de luxe program has clearly come to stay, and 
the tendency is toward greater program variety. 

For this purpose the exhibitor, as will be seen, must have short 
features. Experience has established the two-hour show as a suitable 
length. Experience also teaches that a well-diversified program with 
six or seven numbers is far more attractive than a program in which 
the feature runs the full two hours. Let us prepare an imaginary 
program : 

Every bill should contain an overture. We have found this an 
ideal number if about eight minutes long. Every second more than 
nine minutes takes away from whatever success you may have been 
achieving with the crowd up to that point. Take note that this makes 
the selection of overtures something to engage attention — to get 
varietj^, appeal, and proper length. 

Every bill should contain a weekly film news number. I consider 
the weekly, if good, next in importance to the feature. We have 
tried all sorts of lengths and have made up our minds to certain 
things. First, if less than six minutes in length, the weekly leaves the 
audience dissatisfied. The average subject runs somewhere between 
one and one and one-half minutes. Five subjects are too few. Second, 
you can show news up to fourteen or fifteen minutes without tiring 
your audiences. Feature lengths, however, are such that we usually 
do not show news above ten minutes. We take all four news services, 
and make for ourselves a composite Eastman Theatre Current Events. 

Every bill should have an act. This can vary all the way from 
the tableau shown for half a minute or so, which we have to arrange 
when we get a long feature, to a big act of twenty-five minutes. We 
rarely exceed ten minutes for an act, since, if we have time, we find 
it better to program two acts instead of one. 

Every bill should have a comedy or novelty film of some kind. 
It diversifies the show, and it is practical, too, for if placed after the 
feature and before the overture, it permits the seating of the crowds 
before the overture starts. 

Now, to sum up, we have this time-table: 

Overture 8 minutes 

Weekly 10 minutes 

Act 10 minutes 

Comedy or Novelty 10 minutes 

If we take these as our minimum, a feature film that runs longer 

50 Transactions of S.M.P.E., January 1926 

than an hour and twenty-minutes will hurt its own chances of success 
by its length. 

What can be done in the art of concise presentation has never 
been demonstrated to better purpose than in "He Who Gets Slapped," 
where a story of intricacy, full of details, was excellently presented 
in a seventy-minute film. This was a great credit to Metro-Gold wyn 
and to Victor Seastrom, the director. Had this been a longer picture, 
I do not think it could have made so remarkable a success as it did. 
When pictures are longer, we can do three things: (1) reduce the 
number of items in the program ; (2) cut the picture ; (3) run it faster. 
Of the three, it is clear that we least of all wish to sacrifice variety. 
As to cutting, we recognize that the producers ought to be more 
competent to cut than we are ; yet, I am frank to say that during the 
past year we have had many features come to us in a condition where 
the elimination of some hundreds of feet actually improved the 
success in exhibition. I could mention several features which time 
did not force us to cut, but which we cut for this reason. As to the 
speed of projection, this subject has already been discussed before 
your body on previous occasions. Your organization recommends 
eighty-five feet per minute. I believe, myself, that ninety feet per 
minute is more satisfactory from the audience point of view. I know, 
and I have no hesitation in admitting that, when we showed the 
"Ten Commandments" a few weeks ago, it was necessary to run the 
entire feature at a speed of one hundred feet per minute. This may 
be bad engineering, but the remedy lies with the producer and not 
with us. 

Bear in mind that in making up the program as we did just now, 
I was including only the necessary minimum of diversification. The 
ideal program would be made up of seven numbers instead of five. 
It is a commonplace among exhibitors that you cannot attract an 
audience with scenics; yet, it is no less true that a good scenic picture 
not exceeding six hundred feet in length, if well accompanied musi- 
cally, will get the audience in the required frame of mind and will 
prepare them for a greater enjoyment of that which follows. I 
believe in two reel comedies. No bill is complete without a good 
laugh, and while the old-time slap-stick has been done to death, the 
producers of first class comedies have so far shown no lack of ability 
to think up amusing situations. The short comedy with a real 
story is at last coming into its own. 

An Exhibitor's Problems in 1925 — Clarke 51 

Taking the program as a whole, the most difficult part to arrange 
satisfactorily is an act. We have found by experience that grand 
opera and ballet divertissements have no more place in the de luxe 
program than jugglers or balancing feats extraordinary. Our knowl- 
edge of the successful act is in the main negative. We know that our 
composite audience is not satisfied if we merely transplant items 
from other types of entertainment, such as opera and vaudeville. 
We know also that they are entitled to something more than straight 
concert numbers. Furthermore, I do not believe in prologues. An 
atmospheric prologue can sometimes be arranged successfully where 
the aim is to get the audience into the right frame of mind for viewing 
a feature picture, but there is little sense in presenting an act based 
on a picture which the audience has not seen. The motion picture 
acts offer at the present moment the biggest field for experimentation. 

To sum up, our problem in program making, expressed commer- 
cially, is the desire to get the people to come to the theatre in the 
expectation of seeing a good show rather than to decide according 
to the attractiveness of the feature picture alone. Until we succeed 
in this endeavor, we shall be subject to the wide fluctuation in drawing 
power of the feature pictures. 

The feature will, of course, in every program remain the head- 
line attraction around which the program must be built. The feature 
represents the universal solvent. It is the common ground on which 
all sections of our audience will meet. The producers know that in 
selecting the feature to be shown we must not flout any section of our 
public. They know that motion picture features must always appeal 
to the masses. Books may be written and published with numbered 
copies autographed by the author for private circulation only; plays 
may be produced in bijou theatres for a hand-picked public; but 
motion pictures will fail unless they appeal to large numbers. The 
exhibitor operating a large house with a heavy overhead per week 
does not like to take chances. He naturally prefers the so-called 
"box office" pictures. This is the stock explanation given by pro- 
ducers in answer to the question, "Why are the movies so 'samey'?" 
Regarded in this light, I am frankly surprised that there has been so 
much artistry and enterprise shown in the production of motion 
pictures; for in the great run of movie houses where the feature 
film is almost the only attraction, the exhibitor is not likely to see 
the argument against the ''sameyness," when the risk of a loss on 
the presentation stares him in the face. I believe that the develop- 

52 Transactions of S.M.P.E., January 1926 

ment of the de luxe program, paying as it does the highest film 
rentals, is the biggest individual step in the direction of rewarding 
the producer who has dared to make something out of the ordinary. 
A well diversified program asks for this variety. The unusual picture, 
if carefully presented in this manner and honestly advertised, can be 
made successful. The American premier of ''Siegfried," which we 
showed in our smaller house last Easter for a week, played to ninet}^- 
five per cent of theoretical capacity. 

Unusual pictures are all the time being produced. The trouble is 
that they do not always get a showing over the country. The exhibitor 
is not to be blamed for failing to see the possibilitjdn an unusual picture. 
Rather, if blame must be given, it hes with the distributor who too 
frequently fails to offer the picture in its correct light from a fear that 
the exhibitor can only be successfully approached by extravagant 
praise and box office allurement. The public has undoubtedly been 
misled, partly b}^ the wrong kind of advertising posters, as I said 
before, partly by the presentations of old stories with new titles which 
often have nothing to do with the subject matter of the feature. 
The exhibitor in consequence has been misled into the belief that the 
public wants only the type of picture to which the public has pre- 
viously responded. He has no accurate means of telling w^hether the 
public who responded to his advertising actually enjoyed the per- 
formance. This, by the w^ay, is the fundamental advantage that we 
in Rochester feel we have over those operating theatres on Broadwa3\ 
We do not enjoy the floating population of the metropolis, and our 
size is such that report by word of mouth brings a direct result at the 
box office. We find today that a successful presentation in New York 
is no assurance of a successful presentation in our own theatre. 

Being the biggest theatre in Rochester, the Eastman is able to 
make its own choice of all the features which we may consider best 
for it. In the attempt to make this an intelligent choice, I have 
during the past twelve months personally screened just about 300 
features. From this total come the 52 which the Eastman Theatre 
presents during the j^ear. Of these 52, I frankly have not seen more 
than fifteen that could be classified as important contributi3n3 to 
the art. The other 37 consist of what are called "program pictures," 
pictures for the film fans, m-ost of them presenting individual stars 
who have a large following which will stick by them without regard 
to the merit of the particular feature. I presume that, as on the 
legitimate stage, big names will always be an attraction. It is interest- 

A71 Exhibitor^ s Prohlems in 1925 — Clarke 53 

ing to note, however, that there is a slowly growing pubUc taste for 
the feature filni which aims primarily at the storj^ and the careful 
casting for tj^pes rather than for the presentation of big names. 

It goes without saying that we sometimes make mistakes in the 
selection of pictures. TMien judging a picture "cold" in the screening 
room, it is often difficult to imagine oneseK a member of the audience 
in the big house with orchestra accompaniment and other trimmings. 
Feature comedies are particularly hard to judge in the screening 
room. It is almost impossible to teU where the big laughs are going to 
come. The response varies with the different showings. Laughter is 
contagious, and a nine o'clock audience wiU. often roar, while a five 
o'clock audience wiU sit in silence because the house is only half full. 
When I say that w^e make mistakes, I mean errors of commission 
rather than omission. For each instance where we fail to present a 
successful picture in the Eastman Theatre, I can think of at least 
seven instances where our expectations of success were misplaced. 

It is very hard to single out any particular common cause 
of failure, but I might Hst some of the reasons why pictures fail. 
Most producers seem to oveiiook the fact that motion picture houses 
operate on continuous performance and that more than half the 
audience arrives during the showing of the feature and stays for the 
beginning. The story and sub-titles must always be so arranged that 
the picture will not be entirely unintelhgible to those who have 
arrived after the beginning. The action must always be interesting 
no matter what reel is being shown. With this thought in mind we 
now screen pictures beginning with the third or fourth reel. 

A common cause of failure is to be found in pictures which have 
been conceived at too great a length and then boiled down to movie 
length. Occasionally certain pictures strike us as disjointed and 
scrapp}'. I do not know whether this arises from the disjointed 
manner of production technique, but it is a pet theor}^ of mine that 
slowness in studio production and the high quantit}^ of retakes on 
scenes is bound to communicate itself to the audience in the form of 

Most features which we see nowadays are long on execution but 
short on idea. The public is appreciative of good photograph}^, 
costumes and sets — particularly of good casting. It is the ideas that 
are usually lacking. This is evident from the frequency with which 
a successful idea is copied. In comedies j^ou see old gags used over 
and over again. In features you find one outstanding success followed 

54 Transactions of S.M.P.E., January 1926 

by such a deluge of similar pictures that the public taste soon cloys. 
Sheik pictures gave place to flapper pictures. These soon passed and 
at the moment we have a succession of "Covered Wagon" sequels. 
There are at this moment some historical western pictures of such 
outstanding merit that one could forecast another success such as the 
' 'Covered Wagon" achieved were it not that the recollection of the 
original success is too clear in people's minds. 

Undoubtedly the most important cause of failure hes in trite 
story material. You start to screen a picture. You see a hackneyed 
story obviously building up to a situation. It beguiles the time to 
call the plays. It is as good as a ball game for you are more often 
right. Whoever has crossed the mountains on a railroad train must 
recall seeing far below the station which the train is not due to reach 
for another hour. After staring for a while, the attention wanders 
and you wake up at your destination. The best ball games are those 
where the result is uncertain until the last man is out. Suspense 
carefully maintained up to the last reel is about the most certain 
assurance of success. Only too often is this overlooked in the desire 
to present the unusual. This desire often degenerates into forced 
situations from which the scenario writer cannot extricate his char- 
acters gracefully. This results in the "last reel flop," the feature 
ailment that almost always proves fatal. Whenever we find ourselves 
wrong in calling the plays, we are dehghted, for here may be the 
"new twist," the thing we can be sure that the audience will appreciate. 


Mr. Clarke: One thought has come to me since preparing this 
paper. Some time ago we had to address the camera college of the 
Fox Film News, and I took up with them one subject which we had 
difficulty with; namely, the awkward speed of marching shots in 
weekly film reels. It comes back again to this question of speeds. 
If this society is correct in setting its footage speeds, there has 
got to be a change in the industry, because the weekly film news are 
instructing their men to shoot at 16 frames per second, and we are 
exhibiting at 24. Whenever we have a marching subject in a weekly 
film, we try slowing it down to the point where the marching looks 
right, but then we always find flicker. The Fox people issued an 
order that marching shots should be taken at 85 feet per minute 
with 'the idea that it should be taken at the exhibiting speed. It had 

An Exhibitor^ s Problems in 1925 — Clarke 55 

a remarkable effect while it lasted, but the matter has lapsed, and 
they are being taken again as they were before. Those of you who 
have seen ''The Phantom of the Opera" will recall seeing the musical 
director beating time. It is impossible to run this correctly. 

Mr. Richardson: I regard this as one of the most valuable 
papers presented to this society. It is, however, quite typical of the 
exhibitor in one respect. In all my experience in the industry, 
covering a period of many years, I have yet to find the exhibitor who, 
without prompting, will lay any stress whatsoever on the importance 
of the manner in which the picture is placed before the audience — 
those various things having immediately to do with the picture 
upon the screen as the audience sees it. By this I do not mean the 
play, as such, but the image seen upon the screen. 

It is unfortunate, and, I do not say this in criticism, that in a 
paper of this sort Mr. Clarke has not drawn attention to the evil 
effect of faulty projection. I say this because, while those in theatres 
of the type of the Eastman have to all intents and purposes perfection 
in those various items which go to make up high grade projection, 
it is a fact that one of the worst evils the motion picture industry 
has to contend with is that the average theatre (and average as here 
used means a vast majority of theatres) does not have high grade 

It seems to me there was great opportunity for Mr. Clarke to 
do a service to the industry by stressing the importance of high 
grade projection in this paper for the benefit of those who sadly 
need to have that point emphasized to them. 

I believe Mr. Clarke overlooked one other thing which is of 
vast importance, namely, color effects such as are now being used in 
many motion picture theatres. Taking the Capitol Theatre, New 
York City, as a convenient example, I firmly believe that a large 
percentage of the people who patronize it do so in preference to 
patronizing other nearby theatres because of the wonderfully beauti- 
ful color effects used in the Capitol. 

I should like to ask Mr. Clarke whether the wonderful hand 
colored pictures, such as were put out by Pathe Freres along about 
1906 to 1908, would not be a welcome addition to the program of 
today? They were mostly "trick" pictures, such as a girl dancing 
inside a bottle, etc., but they were wonderfully effective and beautiful. 

Also, what was the relative cost of gettting a 90 per cent attend- 
ance in those 90 per cent programs? By this I mean to ask if addi- 

56 Transactions of S.M.P.E., January 1926 

tional advertising was responsible for a part of the attendance at 
those shows. Also, what is the relative value of the "star'' in the 
matter of box office pulling power? 

I desire to compliment Mr. Clarke on beginning his pre -screening 
of features at the fourth reel. As he says, one of the great drawbacks 
encountered by the theatre goer is inability to "pick up the story" 
in many features, if he or she happens to come in in the middle of the 

Mr. Palmer: Mr. Richardson asked whether the name of the 
"star" has anything to do with the attractiveness of the picture; 
that is, the ability to draw people into the theatre. Is the public 
interested as to who directs the picture and who produces it; that 
is, do people recognize that one producer makes better pictures than 

Mr. Clarke spoke of the "Last Laugh'' (]Mr. Clarke's remarks 
interspersed) and criticized it because it had no titles. I should like 
to ask whether this picture with titles would be considered an ex- 
ceptional one by his audience and what their reaction was if he has 
shown it. 

With regard to cranking speed: Mr. Clarke mentioned specifi- 
cally the cranking speed with marching scenes. Is there any other 
place where the difference between the speed at which the picture is 
taken and that at which it is projected is annoying and undesirable? 

Dr. Hickaian: I gathered in listening to Mr. Clarke's paper 
that to fill the largest theatre in any town one has to appeal to a 
ver}^ large percentage, and therefore it is essential that the pro- 
gram shall have a popular flavor, the roping in of the high-brows 
becoming a matter of secondary importance. If that is so, one must 
assume that it is impossible to give the best program in the largest 
theatre in any town; it must be given b}^ the house of second impor- 
tance. Mr. Clarke has based his argument on the behavior of Roches- 
ter and taken the Eastman Theatre as an example. It has the oppor- 
tunity of the best of evei^i^hing, but always one hears the expression : 
"There is a magnificent film at the Regent this week, but the family 
prefer the Eastman building." Dm'ing the last few weeks we have 
had three or four films of outstanding importance : Harold Lloj^d in 
"The Freshman," "The Beggar on Horseback," and "The Street of 
Forgotten Men." The last is a magnificent film; it was the less 
superior Harold Lloj'd picture, which received the advertisement 
and- drew the people. 

An Exhibitor^ s Problems in 1925 — Clarke 57 

There are three kinds of humor: the presentation of the bizarre 
in rapid contrast; the second kind, the joy at other people's mis- 
fortunes; and the third, the mention of the unmentionable. I think 
the Harold Lloyd picture succeeded because Lloyd took his clothes 
off and finally his trousers. I present these arguments in contention 
of the fact that if this is the kind of film the general public must 
have it is not possible to fill the largest theatre with the best pictures. 
On the other hand, the music at the Eastman Theatre is the best 
you can hear. I suggest that in the long run the best has paid : large 
numbers of people go to the Eastman Theatre in spite of the films to 
hear the music which the theatre itself has educated them to like. 

Pictures are no longer a novelty and one must fill the theatres 
not only today but for years to come. Mr. Clarke has said that the 
important thing is to generate a confidence that there is always a 
good show to be seen at your theatre rather than to lure people on 
special occasions by "feature" picture advertising. The definite 
question which I put to Mr. Clarke is: "Does he think this solid 
reputation is best built up by following what is believed to be public 
taste; or by presenting material which is known to be the finest 
available?" I may say frankly that I incline to the latter view. 

Me. Clarke: Answering the various questions that we have 
had: Mr. Richardson's question as to why I omitted color: that was 
not inadvertent, but I felt there was no need to repeat a subject which 
had quite some discussion at your last convention. Of course, the 
color is the most interesting binder or cement that holds the units 
of your program together, but I took it for granted that those attend- 
ing the convention were familiar with the paper by your president 
and Mr. Townsend on the work done at the Eastman Theatre. 

The question of the revival of the hand-colored pictures: I am 
personally not enthusiastic for the revival of old films in a house of 
the type of the Eastman because there are only fifty-two programs 
open, and we want to have this given over to the new program, but 
we have, every Saturday morning, the films of the Hays organization 
and the interesting color pictures of years ago should find their place 
in those programs. 

Mr. Richardson: I didn't mean to revive the old subjects but 
the old process. 

Mr. Clarke: With respect to hand coloring, I believe that the 
development of the color processes has already reached a point where 
hand coloring can be detected and appears poor. 

58 Transactions of S.M.P.E., January 1926 

Mr. Richardson: I think you have effects there which it 
would be impossible to produce in the natural colors. 

Mr. Clarke: Well, I am inclined to think that the thing which 
appeared so attractive years ago would not today when you have had 
a succession of pictures with colored sequences. I think most of the 
features have been in Technicolor, and those already have reached 
the point where the hand color does not stand up. We have screened 
a large number, and I have not felt justified in taking them for the 
Eastman although I have two other theatres to operate. 

As to the "star" value: This is assured value. The program 
picture with the established star is like so much sugar in the grocery 
store ; it is the one sure thing the exhibitor has in a business that varies 
tremendously. The fluctuation between features from week to week 
is like a saw-tooth; the fluctuation of pictures of certain stars is less 
so. Let us take the Swanson group: you will find less fluctuation, so 
that the exhibitor who showed the last picture and is dating the 
next can be more nearly certain of the volume of business to expect 
from it. I could say a lot about the star business from the exhibitor's 
point of view. I didn't include it because I thought it foreign to this 
body, but I feel that there always will be stars, and if only the 
vehicles for these stars can be more carefully supervised, the exhibitor 
and the public will gain by it. We have had the experience of stars 
who are steadily on the down grade. We have certain stars who are 
too directly classified in the type of work they are showing. I have 
particularly in mind the Corinne Griffith pictures, all of which, until 
the last one, have had a certain smack which is not wholesome. There 
is now an attempt to rebuild the damage which need not have been 
done. It need not be that the star will be the outstanding attraction, 
more so than the subject matter. Some day, the ideas will catch up 
with the execution. When they do, the star will be relatively less 

Mr. Richardson: I asked about the advertising in a 90 per cent 

Mr. Clarke: We hardly fluctuate advertising in Rochester at 
all. I allow the publicity director a gross sum for the year which 
averages so much a week, but his departures are very slight, because 
we appeal to the same audience each week. This would apply more 
to a house which was not doing a neighborhood business, and the 
Eastman Theatre is in reality only a large neighborhood house. 

Mr. Richardson: The feature does, however, have a tremen- 
dous influence. 

An Exhibitor^ s Problems in 1925 — Clarke 59 

Mr. Clarke: Oh, yes. The feature is the outstanding thing at 
this moment in the program. Our only idea is to fill up the valleys 
in this saw-tooth by giving a quality of program which would in- 
crease the minimum. 

Mr. Palmer asks whether the director has an influence. If I am 
not mistaken, it is only within the last few years that we have had 
the featuring of the director to the public. It has been very necessary, 
and we include the name of the director in our program. If the 
producers feature the individual the exhibitor will pass it on to the 
public, and the public will become more discriminating. That is 
bound to come. I think it was Wid Gunning who was first in telling 
producers that they should feature their directors, and I think the 
next thing will be to feature the camera man, that is, the technical 
expert. At present the list of credits is so long that it means nothing ; 
we rip it out because we print a program. 

With regard to the producer: I don't think the public cares a 
hoot under whose name the picture is published. The point is that 
when a concern is producing a large number of pictures it is going to 
produce all kinds, and in producing all kinds it will produce some for 
one audience and some for another, and the same individual may 
enjoy one and loathe the other, so that the institutional name is not 
worth much. The house that picks and chooses its features has no 
benefit to gain by popularizing the producing company. 

As to "The Last Laugh,'' this was titled and was shown, I 
believe, in Los Angeles with titles. This was about the most horrible 
idea I could conceive. It could not improve the picture a particle. 
"The Last Laugh" was not suitable for the continuous program. If 
we had had our smaller "two-a-day" house available at the time 
we got the picture, that is where it would have been played. It should 
not have been shown for continuous program because it was unin- 
telligible to anyone arriving after the beginning. It remains the finest 
artistic achievement ever made in motion picture presentation. 

Projection speeds: Frequently, if we are forced to hold to a 
tight schedule, we will run the picture at a certain speed and slow 
down on the titles; we can run a scene fast where there is mere 
gesture. We have a most elaborate cue sheet issued by our pro- 
jectionist to his men. I am sorry this is necessary, but the confines of 
the two hour program have yet to be recognized. I was talking to 
Mr. Marcus Loew about this last summer and said I was gratified 
to see the six or seven-reel features produced, and he said that this 

60 Transactions of S.M.P.E., January 1926 

was no accident; they had recognized this as exhibitors. Famous- 
Players is coming to this very rapidly. First National, on its own 
productions, has not yet seen the light. 

With regard to /The Street of Forgotten Men": The exhibitor, 
after all is in business, and while in the particular Eastman Theatre 
I don't have to show any profit, I have no endowment, and I must 
run the Theatre so that it will attract the largest audience. You 
can measure the success of a picture only by the size of the audience. 
I thought "The Street of Forgotten Men" was one of the best pictures 
of the kind I had ever seen, but it is one on which unfortunately we 
could only expect a limited audience. I am not trying to arrange 
that the Eastman have all the good pictures and the Regent the 
poor ones; I am trying to arrange them to get the best audience for the 
picture. This picture could have been presented at the Eastman, 
but I think it would have fallen below the average. At the same 
time we are not strictly commercial. We had "The Beggar on 
Horseback," — a picture five years ahead of the public taste. The 
Eastman owed it to the industry to present that picture with a big 
orchestra, but we died with it. I might sum up the point by saying 
that Mr. Eastman did not build the theatre with the idea of duplicat- 
ing the type of performance given elsewhere. Mr. Richardson's 
ideas strike me in this way. I am not so much concerned with the 
rest of the exhibiting world. If they want anything we have, they 
are welcome to it without charge. The color presentations are open 
to any theatre that may want to have them. Our idea is to use the 
theatre as a place where we can test out the possible future type of 
threatre presentation, and I hope that our experience will serve as an 
example to those not so fortunately situated. 

Mr. Palmer: I don't think I made my question with regard to 
cranking speed quite clear. Mr. Clarke mentioned the specific 
case where a group of marching men were photographed at a lower 
speed than that at which they were projected. Do you find any 
other cases where you would say that the cranking speed in taking 
would improve the showing on the screen? 

Mr. Clarke: If I get your point right it is this: That the taking 
of the marching shot at the speed of exhibition will give the proposed 
reproduction of the actuality. I mention marching shots because 
that is the place where it is the most important and where the music 
must most closely fit. We can get by with other scenes where the 
projection may be slower; that is, where the relation between the 

An Exhibitor^ s Problems in 1925 — Clarke 61 

original taking speed and the exhibiting speed may be further apart 
without harm. 

Me. Porter: One of the problems which has been discussed a 
number of times in this society is that of reaching the greatest 
number of people, the greatest number of classes of people, interested 
in motion picture work, and we are sadly lacking in our membership 
representatives of the exhibitors. Only recently one of the exhibitors 
resigned, and I have wondered why that is; is it because the material 
which we describe and discuss is of no value to the exhibitor? If this 
is the case, what can we get which is of interest? Mr. Clarke is 
thoroughly acquainted with what we are doing, and while it is slightly 
off from the subject of his paper, I think we should appreciate it if 
he would tell us if the society is of value to him and how we can make 
it more so. 

Mr. Clarke: That is difficult to answer. I have not read the 
Transactions as much as you are giving me credit for doing. The 
exhibitor has a lot to do, and it is only by reason of the fact that 
we are looking for the new and unusual that we can justify our- 
selves in keeping in touch with your organization. I do not think 
that constituted as it is the organization could be of direct benefit 
to the exhibitor; I think it could be of indirect benefit, but when 
I think of some friends of mine in the same line of work, I don't 
think there is much in their daily round of work that they will feel 
they can put aside to keep in touch with the Society. As I look at it, 
it is the one learned society in the whole industry and can take a 
place that will have the most pronounced influence in the tendency 
of the art and will stand within the three essential ends of it; but 
the average exhibitor is concerned with next week's show and not 
with the future tendency of the industry. 


K. C. D. Hickman* 

ONE cannot be certain whether such a dry subject as wash- 
ing will interest this Society even though it is of great im- 
portance to the motion picture industry. 

Because washing is an invisible process and its progress difficult 
to follow, little has been known about it. The important things we 
do to motion picture film are to make pictures on it, develop, fix, and 
project it; and the washing which is involved between some of the 
stages has been regarded as a nuisance. Although everybody recog- 
nizes the need for sufficient washing, exactly how and how long it 
should be done has been left to guess work. 

There is a well known quotation often misplaced as to biblical 
origin that "Cleanliness is next to godliness." Just as lack of godli- 
ness is not apparent till the next life, lack of photographic cleanliness 
is often not effective until the film's next life, that is, until the film 
has passed from its creator to the unfortunate people who have to 
project it. 

I propose to deal with the subject of washing not in the way 
you would like it best as engineers and practical men. There are 
no cut and dried rules which can be applied without mental effort; 
the best I can do is to go through the elementary theory, then the 
more extended theory, and indicate finally how the information can 
be applied to your own laboratory problems. 

Washing of film is largely akin to washing any other material 
with a thin porous surface. Consider the well known action of having 
a bath. If you sat quite still at one end of the bath with a piece of soap 
at the other and then simply got out and jumped into bed you 
wouldn't be clean and you wouldn't be dry. First, you must bring the 
soap into intimate contact with yourself, then you must give the dirt 
time to diffuse out, and then you must rinse away the soiled water. 
Finally, if you didn't dry with a towel, besides catching cold you 
would leave streak marks all over yourself. Motion picture film, 
fortunately, needs no soap, only water for cleaning. Suppose we 
consider the three main processes involved in its washing. The first 

* * Research Chemist, Eastman Kodak Company. 


Washing Motion Picture Film — Hickman 


stage is the application of water and the allowing of time for the 
salt to diffuse out; the second is the mechanical operation of getting 
the freshly diffused salt away from the surface and dispersed among 
the main bulk of liquid; then, thirdly, there is the renewal of the 
water in the tank, analogous to rinsing. One might add a fourth 
stage, — squeegeeing the film before drying, which is the same as 
wiping the body with a towel after the bath. 

You may say "We know all this.'' The question which concerns 
the practical man is what is the quantitative magnitude of these 


Fig. 1 
Diagram illustrating diffusion of salts from emulsion layer 

operations? The}^ are diffusion, agitation, and renewal. We can find 
out the magnitude of any one by making the other two infinite. We 
can find the rate of diffusion of hypo from film by making the agita- 
tion and renewal of water at the surface of the film so great that an 
increase has no effect on the rate of washing. Having found the 
first, by a process of elimination and calculation we can deduce the 
other two. 

Fig. 1 is a diagram of a motion picture film section. A is the base 
or support, B the swollen gelatin full of hypo solution, and C the 

64 Transactions of S.M.P.E., January 1926 

surrounding wash water. For the purpose of our argument we will 
suppose the stirring and rate of renewal of C is infinitely great. In 
what manner and in what time is the hypo going to come out of the 
film B into the water C? You know there is a Kinetic theory of 
gases and solution which supposes that all matter is made up of 
excessively small particles. When a typical "salt" like hypo goes into 
solution, its ultimate particles are unfastened from close solid contact 
with one another and are permitted to wander about indiscriminately 
among the particles of water. They move at high speed for enormous 
distances compared with their own size, but in reality only a minute 
fraction of a millimeter, before they bump into one of their fellows 
and suffer a change of direction. In solution, therefore, the particles 
must be pictured as moving higgledy-piggledy in every direction, 
eternally colliding and proceeding on new paths. It is a property of 
"salts" that the particles can become electrified. If two electric 
wires are placed in solution, the salt particles bumping about acquire 
an electric charge when they happen to hit one of the wires, which 
charge they give up when they wander over to the other.* 

Consider any particle of hypo at the position X in the layer B. 
Whichever direction it moves in, it is sure to meet another particle 
and be given the right about. There is thus no tendency for it to 
leave B. However, a particle near the surface in the position Z, 
should it happen to shoot out into the water, will find no other 
"hypos" there to bump it back, and will be carried away by the 

There is, therefore, a tendency for the salt to diffuse from a 
region of high concentration to one of low; for the particles to move 
from a crowded district to one uninhabited. This is the inner mech- 
anism of hypo removal. We want to know exactly how long this 
process takes for motion picture film. Do the particles in the emulsion 
layer behave exactly as they would in a layer of perfectly still water 
or do they suffer a resistance and cage-like cramping from the jelly 

I must apologize at this stage for referring only to my own work 
and that of my collaborator. Dr. D. A. Spencer, of the Royal College 
of Science, London. It happens that he and I are the only people 
who have been forced in the course of their work to measure these 

^ * This is scientifically inaccurate, but is sufficiently true to complete the 

Washing Motion Picture Film — Hickman 65 

The method used is an electrical one, depending on the increase 
in conductivity of wash water after it has been contaminated with 
hypo. A measuring cell is placed in the water after it leaves the 
main, and a second one after it leaves the motion picture film. When 
any hypo is present the two are out of balance and a humming noise 
is heard in a telephone. By an extension of the scheme the exact 
amount of hypo present can be made audible. 

The Nature of the Washing Process 

Experiments^ have shown that hypo leaves the film exponentially 
down to the least detectable traces, a limit represented by perhaps 
two parts per million in the swollen gelatin. Saying that the removal 
is exponential means that as time proceeds arithmetically the differ- 
ence in concentration between the hypo in the film and the wash 
water decreases arithmetically. The quantity of hypo leaving at any 
moment in proportional to the quantity which remains behind at 
that same moment. It is the ordinary law of organic growth or 
shrinkage and is represented by the equation: dM/dt =K(A—M), 
where K is the washing constant of the film and A the hypo originally 

To the practical photographer the constant K conveys little 
information. He will find the "half -period" a useful guide. The 
half -period, a term borrowed from the science of radio-activity, 
is the time required for the amount of hypo in a film washed in 
running water to decrease by half. 

No matter how much hypo there is present at a particular 
moment, whether 20 per cent or one part in a million, it will take a 
certain exact time, characteristic of the film in question and varying 
from emulsion to emulsion, for half of the amount to diffuse away. 

Suppose the half-period is one minute for a certain motion 
picture film. After the film has been transferred from the fixing 
bath to the wash water, a time will be reached when the film holds, 
say, 8 per cent of hypo. Exactly one minute later it will hold 4 per 
cent, and a minute after that 2 per cent, and in another minute half 
of 2 per cent or 1 per cent, and so ad infinitum. 

The writer has found, by means of the electrical testing appara- 
tus^ previously referred to, the half -period of a large number of nega- 
tive and positive emulsions and found that it varies between the 

1 Hickman and Spencer, Phot. Jour., 1922, 46, 225. 

2 Hickman, Phot. Jour., 1923, 4?, 208. 

66 Transactions of S.M.P.E., January 1926 

extreme limits of ten and forty seconds. No film ever lost haK its 
hypo in less than ten seconds or took longer than forty in a rapid 
stream of water.^ Negative motion picture film had a half-period in 
all cases examined of less than thirty seconds and positive film of 
about twenty seconds. These figures apply only to an "ideal" stream. 

"Ideal" Washing Conditions 

At the risk of redundancy I will say a word or two about the 
meaning of what may be termed the "ideal" stream. The washing 
law states that the rate of removal is proportional to the difference 
in strength between the hypo solution in the film and that in the wash 
water. When the water is moving in a sluggish stream past the 
surface, the actual layer in contact with the gelatin may be very rich 
in hypo; as the velocity increases the contact layer becomes weaker 
and weaker until it is virtually pure water. Any further quickening 
will give no detectable increase in the rate of washing. The author 
was able to determine the ideal stream under two widely different 
conditions. The first experiment consisted in allowing freshly 
fixed film to wash in a pipe through which water flowed from a 
fully open faucet at the rate of some gallons a minute. In the second 
case the film was suspended in a large box and subjected to a highly 
atomized spray and the drippings from the lower end collected in a 
measuring device. The amount of water used was less than an ounce 
and a half a minute. The rate of washing was followed electrically 
and found to be identical in the two cases. Repetition of the two 
experiments showed that the ideal stream had been just realized; 
increasing the water supply made no detectable alteration in the 
rate of washing, decreasing the flow gave a perceptible retardation. 
In the case of the spray washing, it was possible to calculate from the 
experimental data that the hypo concentration in the film of con- 
densing water was about one-fifteenth that in the emulsion at any 
moment. It would seem, therefore, in the case of the first experiment 
that the water in actual contact with the film must have been con- 
taminated to a similar degree. With the spray every little droplet 
had been driven into intimate contact with the surface and then 
removed by draining to make way for successors; with a large stream 
less than one per cent had been near the film, the rest, like the fellow 
travelers of the gentlemen who went down from Jerusalem to Jericho, 

■ ^' Hickman and Spencer, Phot. Jour., 1924, 48, 537. 

Washing Motion Picture Film — Hickman 67 

had passed by on the other side. The use of an ideal stream, there- 
fore, does not involve expensive apparatus or impossible experimental 
conditions; it simply means that the water shall be violently agitated 
at its actual point of contact with the film. We can consider the 
effect of washing at this speed as though it were quite easy to realize. 

Washing Calculations 

Let us assume the average half-period of motion picture film 
under ideal conditions to be twenty-five seconds. Then, in two 
hundred and fifty seconds the concentration will have fallen to 2~^° 
times or to 1/1024 its original value of, say,. 20 per cent hypo. Now 
a hundred square centimeters of emulsion in the average swollen 
state induced by half an hour's immersion, occupy about one cubic 
centimeter. In this volume there will be 1/5000 of a gram of hypo, 
or half a milligram. The quantity of silver in a similar area of film 
of optical density 1 is about 0.01 grams. There are many theories of 
fading, but it seems generally admitted that the hypo must act by 
virtue of its nascent sulphur or by supporting bacterial life, in which 
case both sulphur atoms are available. 

Concerning Fading 

Pursuing the latter assumption, we may write the equation: 
4 Ag2+Na2S203,5H20+C02+bacteria-|-gelatin 
. 2Ag2S-|-Na2C03+more bacteria + oxidized gelatin 
Then, 4X108, or 416, grams of silver will be attacked by 248 grams 
of hypo. To alter the whole of the deposit of density 1 in a square 
decimeter, we shall require 0.01 x|^^, roughly 0.005 grams of hypo. 
At the end of the 250 seconds washing, however, all but 0.0005 grams 
of hypo have been removed. There is thus only enough left to cause 
the fading of one-tenth of the deposit. The "fading" is merely con- 
version to the brown sulphide and is not noticeable except when 
very bad. The hideous discolorations which are sometimes met with 
are produced by quantities of hypo enormously in excess of anything 
we are discussing here. Fading according to this equation probably 
only occurs under exceptional conditions in hot damp climates. In 
the ordinary course of events the action is purely chemical, thus: 

2Ag+Na2S203+i02 =Ag2S+Na2S04 
Most of the sodium thiosulphate is oxidized and destroyed while the 
damp film dries. 

68 Transactions of S.M.P.E., January 1926 

The Properties of Tanks 

Practically, the ideal washing stream can only be realized by 
use of a spray or an extravagantly wasteful flow of water. When 
film is placed in a tank whose contents are vigorously stirred, equilib- 
rium is attained in the quickest possible time, that is to say, the 
washing is ideal down to the limits imposed by the contaminated 
wash water. After that the film has to wait until the water becomes 
changed sufficiently to complete the process. 

Consider water flowing continuously into any vessel and passing 
to waste at the same rate, so that a constant level is maintained. 
If vigorous mixing is allowed, the waste water consists partly of 
stale fluid, partly of fresh, and after the passage of unit volume 
through the tank the concentration will have fallen to half; of two 
unit volumes to one-quarter, of three to an eighth, and so on. The 
concentration in the tank is falling according to the same law as 
obeyed by the film ; only the half -periods vary between much greater 
limits. A spray hitting a vertical film may have an effective half- 
period of less than a second; a tank which takes an hour to fill will 
have a half-period of one hour. 

It is a property of a series of exponential numbers that their 
logarithms plotted against time as a linear function give a straight 
line. The typical die-away washing curve of motion picture film 
plotted logarithmically yields a straight line. When, however, the 
log. washing curve of the film in a big tank with well stirred contents 
is obtained it has the form shown in Fig. 2. The portion a is the ideal 
film curve slowly merging into h, which is the water changing capacity 
of the tank. This capacity is quite simply the ratio of influx to volume. 
For efficient washing it should have a factor near the half-period of 
the film. It becomes quite impossible, however, to circulate a hundred 
gallons a minute through a hundred gallon tank. There are only two 
remedies: one is to abandon large vessels, the other is to wash by 
changes or in cascade.^ 

If the film is transferred successively through a cascade of, say, 
five baths in which water is circulating in a counter direction, the 
hypo may be allowed to accumulate until each bath contains perhaps 
one-tenth of the one previously. The first bath will, therefore, hold 
one-tenth of 20 per cent hypo or two per cent, the second a tenth 
of 2 per cent, while the fifth will be virtually pure water. The final 

' * Hickman, Kine Weekly, Dec. 25, 1924, 49 and Jan. 1, 1925, 110. 

Washing Motion Picture Film— Hickman 


concentration of the film will be somewhere about 10~^ of 30 per cent, 
or one part in five hundred thousand. Yet the water which ultimately 
passes away with 2 per cent of hypo is the same water which has 
previously been used for the refined cleaning of the film. 

Practical Recommendations 

Owing to the fact that the washing arrangements in most 
processing machinery are already installed, it is not easy to give 










\ \ 



\ \ 


\ \ 

t? 100 


\ \ 
\ \ 


\ \ 


\ \ 


■* — ^ 

\ \ 


""^"^- \. 



\ ''"^-^"'^ 



"~ •c*::^.^^^^ 















^'~'''*— ~» 


1 1 

_l 1 1 i 

too 200 300 400 500 600 700 600 

Time in Seconds 

Fig. 2 
Typical graph showing merging of film washing curve with tank washing 
curves. The figures for concentration of hypo, i.e.^ ''washing'' are plotted 

revolutionary advice for the improvement of washing. Explaining 
as we have done the theory of hypo removal to those operating a 
developing plant will probably enable them to increase its efficiency 
better than concrete recommendations made in the absence of 
knowledge of their exact requirements. However, the following 
remarks may be useful. 

In small studios where motion picture negative is often de- 
veloped by hand on wood frames, the efficiency of the washing tanks 

70 Transactions of S.M.P.E., January 1926 

can be increased tenfold if they are never allowed to become con- 
taminated by surface hypo from the freshly fixed racks. 

This surface hypo can be removed by a few seconds' rinse in 
a separate tank which need have no water flowing through it but need 
merely be filled afresh each day. A better method is to spray the 
rack from a rose at the end of a flexible pipe. Care should be taken 
that water finds its way between the woodwork and film so that it is 
not only the emulsion side which gets sprayed. 

From time to time suggestions have been made for the complete 
washing of film by sprays. It has always proved useless where 
racks are employed because the spray never cleans the hidden wood- 
work sufficiently to prevent diffusion onto the emulsion side when the 
film is unwound later. Resort is generally made to tanks. 

The design of tanks presents little difficulty from the point 
of view of washing, however troublesome the constructional details 
may be. Tanks should be as small as will deal with the film output. 
The smaller the volume, the more quickly the stale water is replaced. 
The entrance and overflow pipes should be situated as far apart as 
possible. Contrary to accepted practice, it is not necessary for the 
exit to be at the bottom. Except in the beginning stages gravity 
has no effect on washing except in absolutely still water. Still water 
is to be avoided because it gives poor washing; hence, provided they 
be far apart, the entrance and exit pipes may be placed wherever 
convenient to the engineer. Similarly there is no advantage in having 
the water entering by a number of holes along a length of piping. Each 
stream sets up an eddy current which is interfered with by the 
next. It is better to let the water enter in one vigorous stream which 
will set up a strong current in the bath. 

The washing arrangements in use with continuous processing 
machines comprise sprays, tubes, or tanks. In tube machines the 
film travels down a succession of tubes containing fresh water, whence 
it passes to the drying machinery. We once saw a developing machine 
in France where the film passed in succession through six tall vertical 
pipes. Water was fed in parallel through the first three, and thence 
in parallel through the last three. This is emphatically inefficient 
procedure. The whole of the water should have been directed into 
the top of the sixth tube, out of the bottom, and into the top of the 
fifth and so in series through the whole number. The hypo laden 
film w^ould have entered the first tube, met dirty water, which, 
however, contained many times less hypo than the emulsion, and 
proceeded into cleaner water as it itself became clean. 

Washing Motion Picture Film — Hickman 


Because there is bound to be a lot of mechanical transference 
of hypo from the fixing solution, just as there is with racks, however 
efficient the tanks or cascade tube system, it will pay to install a 
rinsing loop to secure the same action as the spray recommended 
for use with the wood frames. This is shown in Fig. 3. 

The film leaves the hypo bath and is carried over three rollers 
to form an inverted spiral loop and thence into the washing tank or 
tube. The inverted loop is contained in a box which may be filled 
with overflow water from the wash tank. Vigorous agitation is 

To Wash Tank 

16 Was-he. 

Fig. 3 
Einsing tank for insertion in continuous processing mac?iine 

essential, best secured by compressed air. Alternatively, a spray of 
atomized water from a nozzle fills the box with mist and rinses the 
film equally well. 

It was emphasized early in the paper that agitation is essential 
if all the water in the tank is to be brought in contact with the film. 
There is probably no stirring agent so thorough as compressed air 
admitted to the bottom of the vessel. The bubbles do not depend 
for their efficacy on the velocity of injection but on their buoyancy 

72 Transactions of S.M.P.E., January 1926 

which is effective throughout their passage through the liquid and 
not only near the jet. Large bubbles have this valuable quahty 
that they remove airbells adhering to the film and scavenge away 
the products of recent diffusion. 

Nevertheless, there are many who object to compressed air 
stirring because it involves pumping machinery. Compressors are 
expensive and difficult to keep in good order. If under oiled they 
over heat and wear unduly; if over oiled, oil spray gets into the air 
blast and finds its way onto the film. 

It has caused many photographers who use rack development to 
install mechanical rocking devices to keep the racks in agitation. 
This rack agitation is no substitute for good tank design and suffi- 
ciency of water, but with these, it gives excellent washing. The 
rack is coupled to an oscillating arm which moves it slowly backwards 
and forwards in the direction of greatest resistance to the water. 

Squeegeeing before Drying 

However efficient the washing operation, there must remain 
some hypo in the wash water. The permanence of the film is increased 
therefore if the surface layer of the wash water is removed. Indeed, 
as drying proceeds any water left segregates into droplets which 
shrink down and leave all their impurities in localized areas. It is 
at these spots that fading will begin. This is a reason for squeegeeing 
equally as important as its effect on the appearance of the dry film. 

Procedure in Special Cases 

Conditions obtain sometimes when only a very small quantity of 
water is available for film washing, and the question arises how 
best this can be applied. The answer is to split the water into the 
greatest number of successive changes that can be used without 
making the bulk of each bath too small to cover the film. Consider 
ten gallons of water used in one bath to remove 4 ounces of hypo 
contained in one pint volume of swollen emulsion on a length of 
motion picture film. The hypo will divide itseK in the ratio of the 
volume of emulsion to that of wash water, which is one to eighty. 
The washed film will contain one-eightieth of four ounces, or one- 
twentieth of an ounce of hypo. When ten gallons are used in ten 
successive baths of one gallon the result is much more perfect washing. 
The first bath will reduce the hypo to one-eighth, the second to an 
eighth of an eighth or a sixty-fourth, and the tenth to 1/8^°, an 
infinitesimally small amount. 

Washing Motion Picture Film — Hickman 73 

Nature of Washing Water 

Nearly all town water supplies are suitable for washing film. 
Brackish water, containing common salt, is to be avoided, but lime 
and magnesia, as carbonate and sulphate, are probably harmless, 
and the carbonates perhaps beneficial. Very hard waters merely 
need more perfect surface removal by pneumatic squeegee before 
drying. Iron salts occurring in acid and peaty waters may discolor 
the film, but they are not likely to affect its permanency. Therefore, 
contrary to accepted belief, the nature of the water supply is not of 
vital importance. 

A question which often arises at sea is whether sea water can 
be used in place of fresh. For a couple of soakings of three minutes 
each, yes; but for final treatment, emphatically, no. At least three 
three-minute soakings should be given in a small quantity of fresh 

Tem'perature Effects 

High temperatures cause the emulsion to swell and hinder wash- 
ing in much the same degree as they quicken the diffusion process. 
The net result is that the hypo washes out at about the same rate 
whatever the temperature of the water. This does not apply to 
heavily hardened emulsions which do not swell in warm solutions. 
Film hardened in strong alum or formalin will wash a Httle quicker 
in summer than in winter. In ordinary processing, however, there is 
Uttle detectable change. 

In conclusion it must be repeated that while this paper describes 
no new experimental work, it is founded on material previously 
published by the author in conjunction with Dr. D. A. Spencer in 
other journals. This must be the excuse for quoting our own work 
exclusively in references. It is hoped that the results restated here 
may be of use to those processing motion picture film. 


The nature of hypo removal from motion picture film is examined 
and shown to be an exponential process. Suggestions are made for 
calculating the amount of washing needed to secure immunity from 

The design of apparatus is considered in relation to the natural 
washing properties of the film. 

Rochester, New York, 

September 28, 1925. 

74 Transactions of S.M.P.E., January 1926 


Mr. John Jones: What would be the lowest temperature 
recommended for washing film, and what would Dr. Hickman con- 
sider the minimum amount of water necessary per linear foot of 
motion picture film? 

Dr. Sheppard: I should like to ask Dr. Hickman in reference 
to the experiments with different emulsions whether the differences 
of behavior were due to thickness of the film or whether there were 
any other variables. 

With regard to swelling: This question bears not only on the 
thickness dry but the thickness when wet. Has Dr. Hickman any 
data on this which would bear on the thickness dry and on the 
amount of swelling? 

Mr. Richardson: In the past I have had many samples of 
faded film submitted for an opinion as to what was wrong, but have 
referred the matter to laboratories. I would like to know if the fading 
of film would or could be due to lack of proper washing; also, if film 
can be injured through excessive washing. 

Mr. Crabtree: It has occurred to me that squeegeeing the 
film with a rubber or air squeegee as the film passes from one tube to 
another in a processing machine would help to remove the residual 
solution at the surface and economize with regard to the amount of 
water necessary. I should like to know if Dr. Hickman has tried 
such an experiment. 

Dr. Hickman: With regard to Mr. Jones' query as to the 
lowest temperature possible : The swelling and shrinkage of a gelatin 
emulsion is largely irreversible until you have melted or dried it 
again. If this is the gelatin film (drawing), and you have developed 
it at the favorable developing temperature, and it has swollen this 
distance (indicating), and you wash it at some lower temperature, 
although the natural thickness to which the gelatin would have 
swollen at this lower temperature is half way between these two 
points indicated, at this temperature the gelatin will not shrink back 
unless it is left there for a long time, in which case syneresis may set 
in. With water much colder than the developer, therefore, washing 
will take longer, but where the water is much warmer, washing 
will take place at about the same rate because the swelling will make 
up tor the quickened diffusion. 

Washing Motion Picture Film — Hickman 75 

With regard to the least possible amount of water necessary for 
washing, I could get away with 5 ounces of water per foot if I were 
perfectly sure that the film were in intimate contact with the spray. 
On the European continent sprays are very common. Such a small 
quantity of water must be considered more in the nature of an ideal 
and probably one would have to use more than a pint of water in 
commercial practice. 

With regard to Dr. Sheppard's question, he will remember that 
this paper has been abstracted from three or four others. The re- 
moval is there shown to come down to one part per million, though 
there is a minute amount of hypo left on the image which varies 
from emulsion to emulsion. 

Dr. Sheppard: I was referring not so much to the tail as to 
the cut at the bottom of the diagram. 

Dr. Hickman: It is only the thickness, that is, the active 
thickness of the gelatin at the moment of washing which determines 
the rate. 

With regard to Mr. Richardson's question of fading: That is 
a subject on which I should hke to say a lot. Fading can take place 
under two widely different conditions of use. If you wash down to a 
hundred parts in a million, you consider that the film is adequately 
washed, but if the film is going to hot climates, then any sulphates 
can undoubtedly be acted on by bacteria to produce a form of 
sulphide fading. The amount of washing given a film should be 
dependent on its destination. 

With regard to whether an indefinite soaking injures the film: 
Get the washing over in the quickest possible time. Additional 
washing induces reticulation, which causes the natural clumping of 
the grains to become more pronounced. Also, as the gelatin behaves 
as a culture medium all the time the film is exposed to water, it is 
acting as a camping ground for any passing bugs which may produce 
pitting or have some deleterious effect a long time afterwards. 

With regard to Mr. Crabtree's remark about squeegeeing: 
Mechanical squeegeeing is impracticable between tank and tank 
because of the possible detachment of the emulsion around the 
sprocket holes. Nobody likes mechanical squeegeeing; there is no 
doubt that its introduction will reduce contamination to about half. 
Half its hypo is carried on the surface and half within the gelatin so 
that you will "ginger" up the washing by introducing a system of 
rational squeegeeing. 

76 Transactions of S.M.P.E., January 1926 

Mr. Richardson: You said something about the excess washing 
increasing graininess. Do I understand that excess washing will 
produce graininess? 

Dr. Hickman: I will say that any tendency to graininess is 
increased on prolonged washing. Some of the long soakings given 
where the water changing is poor produces reticulation greatly in 
excess of what a quick wash would have done. 

Mr. John Jones: What would be the lowest temperature 
permissible as an economic measure? 

Dr. Hickman: The point is that you have not got to increase 
the volume for the temperature; the volume needed is determined by 
the amount of hypo coming out of the film and the dilution coefficients 
of your system. An increase in time perhaps of 10 per cent or 20 
per cent of time will be needed but not of volume. 

Dr. Sheppard: May I add an emphasis on the point brought out 
that transfer from warm developer to cold water brings on graininess? 
I made an investigation on reticulation some years ago and found 
that any condition tending tt) produce reticulation increased graini- 
ness, and transfer from a warm developing solution to cold wash 
water would favor reticulation and bring on graininess. 

Mr. Richardson: I would like to add that in the last year or 
two I have had occasion to examine many pictures on screens with a 
powerful glass, and have been astounded at the difference in graini- 
ness of the pictures. I believe if anything could be done to control 
and reduce graininess, it would be most beneficial. I believe Mr. 
Denison will back me up in that. 
Mr. Denison: I agree. 

Dr. Hickman: The essence of the whole thing in not increasing 
graininess is to have the temperature of the wash water the same 
as the rest of the solutions. 


J. H. McNabb* 

THERE is probably no position in the motion picture industry 
that offers more trying and hazardous situations than that of the 
news cinematographer. His exploits in obtaining current events 
of the day in pictures are replete with thrills and adventures that 
would in themselves make suitable material for an ideal adventure 
photoplay. While a considerable part of the current screen news 
material is made by free lancers and is gathered from all corners of 
the globe, many of the larger screen news companies employ a trained 
corps of cinematographers stationed at important cities throughout 
the country, whose major duty is to scoop an important event or 
item of news interest. 

These men are constantly at their posts, many of them having 
police and fire alarm bells stationed in their sleeping quarters, and 
they are on the spot almost as quickly in a catastrophe as are news- 
paper reporters, police, firemen, and others. Of paramount im- 
portance in their work is the equipment which they employ to make 
their pictures. Heretofore they have been burdened by cameras, 
tripods, carrying cases, and luggage, which frequently approximated 
fifty to seventy-five pounds in weight. This heavy equipment is 
usually carried from point to point and set up at advantageous and 
strategic positions. Very often their load is shouldered up ladders 
and fire escapes to attain some particularly desirable location. At 
times they have had to make provision for securely fastening bulky 
equipment in the cockpit of an airplane, and under trying and most 
difficult positions lean out and turn a crank with the plane traveling 
anywhere from 85 to 100 miles per hour. At important events and 
parades they have had to climb to the top of buildings, operate their 
camera, and manipulate the tripod from automobiles, trucks, and, 
in fact, in every conceivable position. 

Now comes a new development in cameras which appears to 
ideally meet the requirements of this class of occupation — the 
Eyemo, a hundred-foot standard automatic camera built by the 

* President, Bell and Howell Company, Chicago, Illinois. 



Transactions of S.M.P.E., January 1926 

Bell and Howell Company of Chicago. With it the news camera man 
can master almost any situation and secure pictures which before 
would not allow the time required to even set up a tripod. Eyemo is 
held in the hand and focused and dialed by sighting through the 
finder tube. (See Fig. 1.) Being automatic, a touch of the trigger sets 
it in motion and photographs instantly any field or action visible 
through the matched viewfinder units, which correspond to the focal 
length of the lens used at the photographic aperture. It will accom- 


I ^^,^, 


Fig. 1. Showing normal position for operating tlie Eyemo Camera. 

modate lenses of any focus from 40 mm up to 20 inches. The change 
from one lens to the other is made almost instantaneously. This is a 
particularly desirable feature for the news man, who may stand off 
at a distance in crowded events and secure close-ups of prominent 
people which otherwise would not be obtainable with the use of a 
tripod. (See Fig. 2.) 

While there is hardly a situation known to the news camera 
man where the Eyemo automatic should not be more practical to use 
and operate than the old crank-turning camera with its cumbersome 

A New Camera for Screen News Cinematographers — McNahb 79 

tripod, it offers for the professional cinematographer some equally 
important advantages. It will eliminate carrying bulky apparatus 
on location and especially over hazardous passes, mountains, and, 
in fact, for almost any difficult elevation. For stunting in the air 
and trick work in comedies, it should be ideal. 

Some of the pertinent features of the new Eyemo, which might 
be mentioned here for convenient comparison with standard crank- 
turning and tripod units, are as follows: 


Average Standard Outfit 

Weight of camera 

, 7 lbs. 

15 to 30 lbs. 

Weight of tripod 

1^ lbs. 

17 to 40 lbs. 


4^X6X8 irregular 

• 5X11X12 

Lens range 

40 mm to 20 inches 

40 mm to 6 inches special 

Interchangeable micrometer 

focusing mountings 


Lens equipment 

Standard f/2.5 

Standard f/3.5 

Kind of operation Automatic Spring Motor 

Hand cranking 





Direct vision upright image, 

Indirect reverse image, in- 

full clear field for each focal 

accurate field for different 

length lens. 

focal length lenses. 


Variable and accurate to 

Pure guess work, two turns 

desired operation. 

of crank per second. 

Lens dials 

Adjustable through finder 

Adjustable only by moving 

tube while in operation. 

to front of camera. 


100 ft. daylight loading 
120 ft. darkroom loading 

100, 200, or 400 ft. 

Footage per 

winding of spring 

35 feet to 50 feet. 

motor (2 to 3 windings 

per 100 ft.) 

It has been determined by actual tests that a spring motor driven 
camera may be operated while held in the hand with uniformly steady 
results when using any focal length lens up to 3 inches. Lenses of 
longer foci, that is from 4 inches up to 20 inches, require the assistance 
of a tripod for steadiness. But the tripod does not need to be a bulky 
panorama and tilting type, now employed with crank-turning 
cameras. Almost any light folding, metal, still camera tripod may 
be employed; the one used with Eyemo weighs only one and a half 

The spring motor is controlled by a governor, which assures 
equal and uniform exposure for each frame, as the film moves at 
constant speed at all times. The motor starts off at full speed the 


Transactions of S.M.P.E., January 1926 

instant the operating trigger is pressed and stops instantaneously 
when the trigger is released. There are no cut-outs necessary in the 
negative because of lag or exposure deficiency in acceleration, nor 
over-exposures in deceleration; also, the camera is always stopped 
with the shutter closed, so that scenes may join each other without 
requiring the cut-outs that ordinarily must be made on cameras 

Fig. 2. Showing set up of Eyemo camera on tripod when using long focus lens. 

turned by a crank. The governor adjustment also permits of setting 
for any desired speed from eight to sixteen exposures per second. 
When set at a predetermined point, the resultant exposure speed is 
accurate within one half of one per cent; the speed also is variable 
while camera is in operation, a feature which will be found very 
valuable in comedy trick work. 

A New Camera for Screen News Cinematographers — McNahh 81 

For faster speeds, that is from sixteen to thirty-two exposures 
an adjustment in the governor at the factory will provide for this 
operating ratio. For superspeed (up to 128 exposures) a specially 
designed governor, spring motor, and gearing may be incorporated 
in the camera frame, but at a sacrifice of the lower speeds; that is, 
it is not possible to provide for interchangeable normal, double 
normal, and superspeed in the same instrument of this type of 


Mr. Crabtree: Did Mr. McNabb send along a model of the 
camera so we could see it? 

Mr. Ziebarth: No, but it is the same shape as the Filmo but 
somewhat larger. It operates in the same manner, and there is 
practically no difference at all between the two. 

Mr. Crabtree: How many feet of film will run through the 
camera at one winding? Is there any trouble at low temperatures? 

Mr. Ziebarth: Thirty-five to fifty feet at all temperatures. At 
one time we had trouble at low temperatures, but we have over- 
come this. 


Herbert E. Ives* 

THE picture transmission system which is now in daily com- 
mercial operation over the lines of the Bell System is to be dis- 
tinguished from earlier efforts toward the same end by two 
features : First, the pictures as received are completely commercial in 
their character; that is, they are immediately available for all sorts 
of technical uses, for which they are in fact practically indistinguish- 
able from original photographs. Second, the system is, unlike earlier 
experimental systems, so worked out that it utilizes without change 
the existing telephone channels, whether these be wire or radio. The 
distance to which pictures may be sent is limited only by the distances 
over which commercial telphone service is available 

The simplest analysis of a picture resolves it into a large number 
of small patches or elements of varying values of light and shade. 
A picture transmission system therefore involves first of all some 
means for analyzing a picture into small elements, or "scanning" it. 
It involves next some means for communicating a record of the values 
of these elements to a distant point. It involves finally some means 
for assuring that the recomposition of the picture elements at the 
receiving end shall place these in their proper relative positions; that 
is, some means for synchronizing the sending and receiving apparatus. 
The scanning of the picture is accomplished in our apparatus 
by first preparing the picture to be sent in the form of a transparent 
film, which may be bent into cylindrical form; this cjdinder is then 
advanced and rotated by a screw motion so that the scanning light 
spot traverses the entire film in a spiral. A similar spiral motion is 
imparted to the sensitive photographic film upon which the picture 
is received at the far end. 

For the purpose of communicating the values of light and shade 
from one end of the system to the other, we use at the sending end a 
photo-electric cell. A small spot of light is focused on the transparent 
film, and, after passing through the film, enters the photo-electric 
cell. The electric current produced in the cell is directly proportional 

* Bell Telephone Laboratories, Inc. — For a more detailed description of 
the method and apparatus here discussed, see "Transmission of Pictures Over 
Teleplione Lines," Bell System Technical Journal, April 1925, p. 187. 


Telephone Picture Transmission — Ives 83 

to the illumination of the cell and follows the variations of light and 
shade instantaneously. At the receiving end, the electric current 
which is controlled by the action of the photo-electric cell passes 
through a narrow ribbon which stands in a magnetic field and by its 
resultant lateral movement acts as a variable diaphragm in an optical 
system through which light from an appropriate lamp is passed. 
The light after passing through this 'light valve" falls upon a photo- 
graphic film and builds up a picture in narrow adjacent strips. 

In order to synchronize the rotating cylinders at the two ends of 
the line use is made of synchronous motors. These are driven by a 
master tuning fork, impulses from which are sent both to the appara- 
tus at the sending end and to that at the receiving end. 

The picture transmission system as just outlined calls for what 
is ordinarily described as direct current transmission for the picture 
signal and for a separate communication line to handle the synchroniz- 
ing pulses. Telephone lines are not ordinarily set up for handling the 
low frequencies which a direct current picture signal would involve, 
and it is furthermore uneconomical to use two separate circuits for 
picture and synchronization signals. For these reasons, both the 
picture and synchronizing signals are impressed upon carrier currents 
of voice frequencies suitable for transmission on ordinary telephone 
lines. The picture signals are carried on a frequency of approximately 
1300 cycles per second, the tuning fork impulses on a carrier of 
approximately 400 cycles per second. Both these alternating currents 
are sent over the same line and are separated from each other at the 
receiving end by means of electrical filters, so that the light valve 
and the synchronous motor each receives only its own proper current. 

In the system as now in operation, the picture to be sent is placed 
on the apparatus in the form of a positive film transparency of size 
5 inches by 7 inches. The pitch of the screw which provides the 
rotation and translation of the film is 100 threads per inch. Pictures 
of this size and grain are transmitted in approximately seven minutes, 
and transmission may be made simultaneously to a number of points, 
as, for instance, from Washington to New York, Chicago, and 
San Francisco, as was done at the inauguration of President Coolidge, 
March 4, 1925. The picture is received as a negative, from which 
any number of prints can be made by ordinary photographic methods 
for distribution to newspapers or other customers. By working 
from wet negatives and using the transparency film at the sending 
end while still wet, the overall time of picture transmission may be 

84 Transactions of S.M.P.E., January 1926 

kept below half an hour; the greater part of the time is consumed 
in the purely photographic operations. 

Pictures transmitted in the manner described meet with a 
number of uses. The widest use at present is in the newspapers, 
which are now able to show, in a few hours, pictures of events happen- 
ing at the other side of the continent. A vivid illustration of this 
use was furnished at the time of the Santa Barbara earthquake, 
news of which appeared in the New York papers in the evening, while 
the following morning papers had a full pictorial record. Another 
large field of usefulness promises to be in connection with poKce 
identification work, not only in transmission of photographs of 
wanted individuals, but of their finger prints. Practical trials have 
shown that electrically transmitted finger prints may be identified 
within a few minutes of reception, thus making it possible to identify 
suspects who, under ordinary court procedure, could not be held 
long enough for the ordinary methods of communicating this in- 
formation. The transmission of signatures and legal documents 
is another field. Medical information, such as X-ray photographs, 
electro-cardiograms, and other information on which a specialist 
can make quick diagnosis lend themselves readily to transmission. 

The use of electrically transmitted pictures in the motion picture 
industry has thus far been confined to the transmission of "stills" 
which by this means may precede the arrival of the film reels by a 
considerable interval. The showing of lantern slides or still pictures 
on motion picture film, exhibiting events of a few hours before in 
distant places, is a possible feature for moving picture theatres to be 
provided by this service. The necessary time consumed in the 
transmission of a single picture would make the transmission of an 
entire moving picture film a lengthy operation. By utilizing pictures 
of coarser grain and special apparatus adapted to handle roll film, 
it should be possible to transmit "flashes" of several seconds duration 
at a moderate cost. 


F. H. Richardson* 

A BRAHAM LINCOLN once said: *'God must love the common 
/-% people, because he made so many of them." Judged by that 
standard the motion picture industry surely must love the 
village theatres, because it has created so very many of them. 

I do not believe the industry as a whole or anyone inside or out- 
side of it, except, perhaps, for a limited, few who have given the 
matter more or less extended thought, have any sort of adequate 
conception of the literally huge importance to the country as a whole 
of the thousands of small theatres located in the villages which form 
the centers of activities for farming communities scattered throughout 
the length and breadth of this great land of ours, and throughout a 
considerable portion of the territories of our Canadian sister to the 

These are the days of excitement. We have arrived at the stage 
of human existence, in this country and Canada, at least, where the 
functions of eating, working, and sleeping no longer suffice to fill 
the human life. Amusement — play — now forms an integral part and 
parcel of human existence. Amusement is no longer regarded as in 
the nature of a luxury. It has become, or rapidly is becoming, a vital 
necessity, especially insofar as it has to do with the younger genera- 
tion. Time was when the farmer boy or girl was satisfied to toil from 
break of day until darkness settled down six days in the week, with 
church on Sundays, perhaps prayer meeting Wednesday evening, an 
occasional neighborhood party winter evenings, and a circus once 
during the year. The farmer boy and girl of that day knew nothing 
different, hence were, pref orce, satisfied with that kind of an existence. 
That day has forever passed. Just what caused its passing we need 
not discuss here. The fact that it has passed is sufficient. The farmer 
boy and girl of today expect and demand their fair share of what the 
modern world terms amusement, or entertainment, and unless it be 
supplied them, indeed because it is NOT being supplied to them in 
any adequate way, they are deserting the farms and villages by the 
tens of thousands, flitting like dazzled moths to the bright lights of the 

* Moving Picture World, New York City. 


86 Transactions of S.M.P.E., January 1926 

cities, where the men are fed into the factories and mills, and the girls, 
or at least many of them, into something far, far worse. 

That this would be to some extent true under any conditions, 
it would perhaps be idle to dispute. We may, however, fairly assume 
that the greater the amount of clean, wholesome amusement and 
entertainment the country or village center can and does offer the 
young people of the community, the greater is the likelihood of them 
being contented to remain where the country needs them most and 
help with the work of the farm, upon which the whole fabric of society 
must depend for its very existence. 

It is to discuss briefly with you the possibilities for providing 
much highly satisfactory amusement and high grade entertainment 
through the medium of the village theatre that I have been moved to 
set forth this argument, with the hope that it may serve to direct the 
attention of men of greater ability than myself who will find some 
practical method for putting into effect the more or less crude ideas 
I shall advance. 

First of all, let us examine into the present situation with regard 
to the village theatre. It is quite true that an occasional privately 
owned and managed small-town theatre which happens to be in the 
hands of a man of exceptional ability puts on a very satisfactory 
and creditable show. Its film service is excellent. Plenty of light is 
used for projection. Its equipment is up-to-date and in a good state 
of repair. Its projectionist is a man of considerable ability, its seating 
comfortable, and its ventilation at least passable. 

All this is true, in greater or lesser degree, with an occasional small 
town theatre. On the other hand, we have a vast number of village 
theatres which are owned or managed by men who know httle or 
nothing about the show business. For the most part, they are men 
who, fascinated by that magic term the "show business," rushed 
bhndly in without any capital to speak of, fondly imagining that 
they had only to get a "machine," some seats, a screen, a room, and 
the public would immediately pour a stream of dimes and quarters 
into their waiting pockets. 

These "theatres" eek out a precarious existence for the most part 
by renting the very cheapest possible junk service, paying small 
attention to decoration, the comfort of their patrons, or to ventilation. 
Some man or boy with little knowledge or experience is hired to 
"operate" old, worn out projectors, using the minimum possible 
screen illumination. The net results can only be termed amusement 
or entertainment by a very great stretch of imagination. 

Importance of the Village Theatre — Richardson 87 

These "theatres" might just about as well not exist at all, insofar 
as concerns their presumed function of providing public entertain- 
ment. As a rule their projection equipment is antiquated, badly 
worn, and very thoroughly inefficient. The screen very often is 
basically very poor, and usually its surface is more or less dirty with 
the accumulations of months, if not of years. Ventilation very often 
is largety a matter of imagination. The music is supplied by a girl 
who drums on a decrepit old piano, apparently with the idea of 
creating as much noise as possible. The films are rainy, battered, 
old junk. 

Nor is this description, terrible as it is, in any degree an exaggera- 
tion in very many cases, though of course I do not mean to intimate 
that there is no medium between this extreme and the relatively few 
really high grade village theatres of which I spoke. As a matter of 
fact, I have spoken onl}^ of the extremes, between which there is 
almost every possible variation. 

However, where the extreme in inefiiciency exists, the community 
of that village and the surrounding country of which it is the center 
is left, to all intents and purposes, without any sort of amusement and 
entertainment other than those few simple ones named in the begin- 
ning, and in this dsij and age such lack is the nature of a calamity. 
I will even go further and say that it is a very serious matter indeed 
for any community to be deprived of really excellent motion pictures. 
I make that last assertion having in view the educational as well as 
the amusement value of motion pictures of today and the further 
value of the news reels in enabling people to actually view most, 
if not all, the happenings of modern life which have large public 

However, the purpose of this paper is not to find fault and point 
out inefficiency and failure except insofar as that may be necessary 
in order that a cure may be suggested for the ill. I propose to suggest 
something designed to be in the nature of at least a partial remedy, 
which may cause you to gasp a bit when you first hear it, but I 
nevertheless ask your very serious consideration of the matter. 

I have tried to show j^ou that village theatres taken as a whole 
are far from what they ought to be. I have suggested that good 
motion pictures, available regularly to the public of farming com- 
munities and small towns, would be of distinct, actual benefit to those 
communities. I think you will all agree that such entertainment 
would, at least to some extent, aid in inducing the young people of 

88 Transactions of S.M.P.E., January 1926 

country places and on farms to be more content with a life which, 
without such things available, is more or less lonely and dull, not to 
say dreary. Obviously such entertainment would also be of distinct 
value to the older people of such communities, who also need the 
education and amusement it would provide. It would, in fact, be 
highly beneficial to them from any and every possible viewpoint. 
The question then is how may it be made available to these com- 

I believe the failure of the average village theatre to provide 
satisfactory entertainment is in great measure due to the fact that, 
as matters now stand, few villages and their surrounding communities 
provide sufficient possible income to pay the necessary overhead 
expense of putting on a really good motion picture show and at the 
same time provide any adequate return to their owners, and it is to 
discuss this very point and to point out at least one way in which this 
situation may be met that I have claimed your attention. 

It is a well established and generally accepted fact that pubhc 
moneys gathered through taxation may be expended in any manner 
and for any purpose which will be of direct benefit to the whole 
of the community from which the said moneys were collected or a 
direct benefit to any substantial part thereof and an indirect benefit 
to the rest of the community, always provided there be no evidence 
of intent to individual favoritism. 

Public moneys gathered through taxation are expended for 
schools and for their equipment and for the employment of teachers. 
Public moneys are expended for public libraries, for their equipment, 
and for attendants therein. Public moneys are expended for the 
improvement of streets and roads. Even though certain individuals 
may never use the schools, the libraries or some streets or roads, they 
nevertheless are acquired and maintained partially at their expense, 
because they are in the nature of public necessities and (or) are 
beneficial to the community as a whole. 

7s it not also true that, under modern conditions, rural communities 
have a very real need for the educational and amuseynent and entertain- 
ment values supplied hy the motion picture? Who would even attempt 
to question, much less dispute, so patent a fact? And if it is a fact, 
pray tell me why public moneys, gathered through taxation, should 
not be used to forward the supplying of high grade amusement, 
education, and entertainment through motion pictures in such 
communities, always provided the expenditure be done reasonably? 

Importance of the Village Theatre — Richardson 89 

And right here the question arises as to just what the term 
"reasonably" might mean when appHed to such a proposal. 

As has been noted, one of the chief stumbling blocks to the 
supplying of a really good motion picture entertainment in the great 
majority of village centers is the fact that sufficient revenue is not 
available to justify men of any considerable business competency 
investing sufficient capital to erect and equip a really good theatre 
building, and the employment of really competent help, and the 
rental of really good ffim service. If all this be done, I think I am 
safe in saying that in four cases out of every five there would either 
be nothing left for the owner when the bills were paid and the interest 
on invested capital deducted or certainly not sufficient would remain 
to tempt a man of real business ability — a man with sufficient ability 
to handle a theatre intelligently. In fact, it is doubtful but that, in 
many communities where such a theatre is sadly needed, the maxi- 
mum possible average income would be insufficient to meet the 
necessary expenses of operation without considering the owner and 
his presumed income at all. 

The possible solution to a situation such as this seems to me to 
be very obvious and very simple. The village community needs 
good roads. It needs a public library. It needs schools. It needs a 
motion ^picture form of enter taimnent. The village authorities would 
not for a moment hesitate to raise money for any of the first named 
purposes by taxation, or at least to order a referendum at an election 
to empower them to raise it or to use any available moneys for roads, 
schools or libraries. They would not hesitate, for example, to author- 
ize a referendum on a proposed taxation for the purpose of building 
and equipping a pubhc library or for any other thing the community 
as a whole stood in need of and for which there was a precedent. 

The village community as a whole, including the surrounding 
farming territory, needs a high class motion picture entertainment 
anywhere from two to six times a week. Would it not, therefore, 
when a new town hall is to be erected, be well to incorporate therein 
a commodious, comfortable, well equipped motion picture theatre? 
Would it not be well that this be done in no niggardly manner, but 
with sufficient expenditure to provide a really good, cozy, well 
equipped little theatre throughout? 

I will myself make the assertion that where no town hall or other 
publicly owned building which would lend itself to such an enterprise 
is to be erected for a term of years, the village might well provide 

90 Transactions of S.M.P.E., January 1926 

and use public funds to build a separate theatre building and to 
equip it throughout in a first class manner. 

In either event, the theatre would be the property of the com- 
munity, and, through its elected officers, be under its direct control. 
The community would thus be in position to prevent the showing of 
objectionable productions and to use the theatre auditorium for 
many purposes other than motion picture shows — amateur theatri- 
cals, public meetings of various sorts, traveling shows, church 
meetings, or bazaars, and even sermons on Sundays, all during times 
when the motion picture theatre function would not be in the least 
degree interfered with. 

Such a theatre could be handled in any one of several ways. 
It could be placed in general charge of a man selected for his ability 
as motion picture projectionist, thus assuring well projected pro- 
ductions, the manager-projectionist to handle the theatre under the 
advisement of such ofl&cial or oflacials of the village as might be given 
charge of the matter, any revenue over and above necessary operating 
expenses to go into the village treasury or any deficit to be paid out 
of it. 

It might be rented or furnished rent free as might seem advisable 
under the individual condition to someone, the admission prices, 
class of film service, and ability of the projectionist to be under the 
control of the village authorities, the renter possibly, under some 
conditions, being guaranteed a fixed minimum income. 

It would also be quite possible for a number of villages which 
required only one or two shows per week to employ jointly a very 
competent projectionist either as a manager-projectionist or merely 
as a motion picture projectionist by so arranging the days upon which 
shows would be given in each village that he could attend to them 
all without interference. This would admit of sufficient remuneration 
being offered to procure a projectionist of ability who could be relied 
upon to give a high grade show, the entire box office income to be 
paid into the various village treasuries. 

However, it is no part of my purpose to discuss details such as 
these in a paper of this sort. In fact, I have small ability in business 
and do not feel myself competent to do so. My whole and sole 
purpose is to try to point out to you the value of the establishment of 
comfortable, well equipped village theatres and their operation under 
conditions which would insure a good programme, well presented 
from the projection viewpoint, all to the end that these communities 

Importance of the Village Theatre — Richardson 91 

be assured of real entertainment in the form of motion pictures plus 
the educational value of many available productions and the visual 
news reels. To this we must add the fact that those who seldom roam 
far beyond the boundaries of their own community may enjoy near- 
travel through motion pictures. 

My proposal amounts, in effect, to a reasonable subsidizing of 
the village theatre with pubhc funds where such a course seems 
necessary in order to insure high class motion picture entertainment, 
and I have tried to show you that such subsidization is fully justified 
by reason of the direct and indirect benefits to be derived by the 
communities at large, as well as by the country at large in a con- 
siderable degree. 

Supply the young men and women of country places with plenty 
of the really splendid entertainment contained in well presented 
modern motion pictures, and a great stride will have been made 
toward checking their rush cityward, which all too often ends in 
disaster, and which in any event merely still further overcrowds the 
already congested centers, at the same time robbing our farms of 
more of their already too scant supply of labor. 

The motion picture has a great mission to perform in this 
respect, but it cannot possibly perform it when placed before village 
people as a dimly lighted discolored, shaky, fuzzy, rainy abomination, 
from which great chunks of the action has been amputated, especially 
if this libel on the motion picture be presented in a crowded, uncom- 
fortable, poorly ventilated and more or less ugly "hall," which may 
only be termed a "theatre" because of the fact that it really does not 
seem to be anything else. 


Mr. Richardson: In preparing this paper I hesitated and 
wondered if it was a matter which would properly come before this 
body. I am very glad I did it, however, after talking with some of 
the members. It is a matter which might well come before this 
society because it is one that could be made of great importance to 
the motion picture industry in expanding its field of useful activities. 
My only hope in preparing the paper was to set before you certain 
ideas for consideration by those able to inaugurate something of 
this kind. This paper might also prove of interest to newspaper men 
if it were brought before them, particularly those who furnish syndi- 
cated articles to rural newspapers. 

92 Transactions of S.M.P.E., January 1926 

if it were brought before them, particularly those who furnish what 
is known as "latent insides" to rural newspapers. 

I don't imagine the paper will provoke much discussion because 
it is a matter one must think over before fully reahzing its importance. 
I don't regard the paper of any large value merely through its reading. 
Its value, if any, will come through the Society getting the matter 
into the newspapers. 

Dr. Hickman: Mr. Richardson's paper strikes me as very 
interesting, but my experience in England, however, is that there 
is a great feeling against anything which draws on municipal support 
or taxation. One knows that the value of good entertainment is 
enormous, but when a body of men like ourselves makes a motion 
that the particular entertainment they are interested in should be 
provided from public funds, the immediate feeling is that they are 
doing more for themselves than for the pubhc. One can see that this 
type of entertainment would be excellent, but in doing anything 
they will do much more for the cinema industry than for the village 
communities themselves. One of the points Mr. Richardson raised 
is that we want to prevent the people who raise food from coming to 
town. What sort of entertainment are we going to show them? 
Are we going to give intensive lessons on cabbage growing or are we 
going to show them magnificent ladies strutting up and down the 
marble halls of town houses? My impression is that the only thing 
it will do is to make the whole crowd of them leave in a bunch. 
We believe that the motion picture in England has been more 
responsible for the vacation of the small towns than anything else. 
I don't wish merely to launch a criticism against a most interesting 
paper. With regard to the existing average theatre, I do agree that 
the condition of the film they get is perfectly disgraceful, and I 
cannot see why it is necessary for a film to have got to this stage 
when it is shown, or why a duplicate print in better preservation 
cannot be supplied by a motor service coming from village to village. 
None of the people will attend the performance more than once, and 
perhaps if the picture were shown only once in each town some form 
of better films on a more economical basis might solve the situation. 
I do not believe that any form of municipal support is good in itself 
or will receive support from the public who have to foot the bill. 

Mr. Richardson: I thought of what Dr. Hickman has said. 
I am partially in a position to refute some of it, because a considerable 
number of villages have incorporated a theatre in their town hall, 

Importance of the Village Theatre — Richardson 93 

and it invariably has worked very well. There has been no protest 
against it, and the theatre may be and is used for many other pur- 
poses. The only question that has not been proved is the use of 
pubHc funds for the improvement of the show. How the public would 
consider that end of it I do not know. The service which village 
theatres, or many of them, are giving is disgraceful, and the result 
is that the people don't attend them. 


Sander Stark* 

BARELY two years ago, the practicability of reflector arc projec- 
tion was a very much debated question. Under certain Umited 
conditions its success in the laboratory or in the hands of an 
engineer was beyond question. To one skilled in the handhng of 
optical machinery, the operation of this type of arc illuminant pre- 
sented no very serious difficulty. But the motion picture engineer 
was confronted with the problem of how the man in the field — the 
projectionist — would react to such an unconventional piece of 
machinery. The field for the reflector arc, obviously, was the small 
and medium sized theatre, where, in so many instances projection 
is in the hands of the more or less inexperienced group of projection- 
ists. The many virtues of the reflector arc — all of which hinge upon 
decreased cost of operation and maintenance — are such as would 
appeal to just this particular class of motion picture theatres. 

The development of the mechanical refinements which led to the 
introduction of the reflector in motion picture projection would 
probably make a very interesting story in itself. There are others 
more intimately connected with this development to whom I shall 
leave the recording of this story. Reflectors have long been used with 
horizontal carbon arcs in immense searchhghts and flood fights. 
They have been used with incandescent lamps both in flood fighting 
and in lantern slide projection for many years. We have employed 
reflectors in motion picture projection in imaging the filaments of an 
incandescent lamp in the interspaces of the filaments themselves. 

In the seventeenth century a Dane, Thomas Walgenstein, 
traveled all over Europe demonstrating a simple form of lantern 
sHde projector in which the optical system of the illuminant consisted 
of a spherical reflector. ^ The Carl Zeiss firm described in their 
catalog of 1911 the optical system of their "Epidiascope"^ — a more 

* Scientific Bureau, Bausch & Lomb Optical Co., Rochester, New York. 
^ Eine neue Spiegel-Projektionslampe. Flinker, Die Kinotechnik, September 
20, 1923, p. 427, Vol. 5. 

^ 2 Carl Zeiss, Jena, "The Epidiascope." Mikro 243. 


Reflector Arc Projection — Stark 95 

or less universal projection apparatus, in which the illuminant con- 
sists of a parabolic reflector in the focal point of which is located the 
crater of a 25 ampere horizontal carbon arc in combination with 
suitable condensers. But it was not until May of 1921 that the 
reflector arc was first introduced in Germany as a unit expressly 
designed for motion picture projection with a carbon arc. And it 
was not until 1923 that the reflector arc fever reached America. 
Indeed, in view of the manifest optical and mechanical advantages, 
the astonishing part of the whole situation, it seems to me, is not 
only that the reflector was not introduced to motion picture projec- 
tion many years previous to its recent inception; but that the re- 
flector, instead of the condenser, was not actually the first optical 
unit in the motion picture illuminant. 

The purpose of this paper is not so much to present material 
that is essentially new, as it is to assemble in a concise way some 
useful information scattered throughout the literature of the past 
three hundred years on the properties of surfaces of revolution 
generated by conic sections as applied to reflectors for arc projection. 
Some of this information, and possibly a great deal of it, may already 
be known to many of you. It seemed, however, a worth while effort 
to gather in one short paper data on the necessary conditions to be 
satisfied in order to procure maximum results from any particular 
reflector system. It seems that if the really important things relating 
to reflector arc projection were presented in this way, — as a sort of 
tabulation of available facts and figures relative to this particular 
field — some of the unnecessary confusion and uncertainty which 
prevails in this field of motion picture projection may be somewhat 

The Spherical Reflector 

One of the properties of a spherical surface is that the radius 
of curvature in all meridians is the same, the surface being generated 
by the rotation of a circle about its diameter. This property, obvious- 
ly, makes a spherical surface very easy and simple of manufacture. 
It is natural, therefore, that a reflector having spherical surfaces 
should have been the first type to be used in reflector arc lamps. It 
would be fortunate, indeed, if a spherical reflector commanded the 
same respect from an optical standpoint as it does from a financial 
and manufacturing standpoint. A spherical reflector is free from 
spherical aberration for an object in its center of curvature — where 

96 Transactions of S.M.P.E., January 1926 

object and image are superposed. For any other position of the source, 
other than the center of curvature, the reflector possesses aberrations, 
which in some instances become exceedingly large. 

The experimental work^ in which we have been interested for the 
past few years, on the improvement in optical performance of illumin- 
ating systems for motion picture projection, has led us to the conclu- 
sion that the factor of prime importance, in improved performance of 
such optical systems, is the correction of spherical aberration. We 
have satisfied ourselves that of two optical systems, each having the 
same speed, same magnification, and same focal length, the system 
which is spherically corrected is far superior to the uncorrected 
system in respect to both quantity and quality or uniformity of 
illumination. It is for this reason that we have laid such great 
emphasis upon the use of spherically corrected illuminating systems 
in motion picture projection and have introduced the use of parabolic 
correcting surfaces in illuminating systems employing condensers. 
The introduction of such corrected condensers was an unqualified 
success. Since it is a worth while effort to spherically correct a con- 
densing system whose angular aperture is of the order of magnitude 
of 60°, it seems as if it should be equally worth while to consider the 
spherical correction of reflecting systems whose angular apertures 
are in the neighborhood of twice this amount or 120°. It is from this 
viewpoint that I wish to bring to your attention the optical efficiencies 
of the various reflecting systems employed in reflector arc lamps. 

In Fig. 1 is shown a curve representing the spherical under- 
correction of an ordinary spherical reflector having, two parallel 
spherical curves for zones up to 60° from the axis. By spherical 
under-correction, we mean that the rays of light from the margin of 
the reflector cross the optical axis nearer to the reflector than do 
the rays of light from zones of the reflector nearer the optical axis. 
This reflector is one that is actually being used at the present time 
in reflector arc lamps in a diameter of 8 inches. In the figure here 
illustrated the diameter has been increased from 8 inches to 8-5/8 
inches in order to allow for the representation of a zone 60° from the 

' "The Function of the Condenser in the Projection Apparatus," H. Kell- 
ner, Trans. S.M.P.E., Nov. 1918, p. 44. 

"Some Uses of Aspherical Lenses in Motion Picture Projection," H. 
Kellner, Trans. S.M.P.E., May 1922, p. 85. 

"A Demonstration Model Showing Lens and Condenser Action in the 
Motion Picture Projector/' S. Stark, Trans. S.M.P.E., October 1922, p. 79. 

Reflector Arc Projection — Stark 97 

axis. The working distance, or distance of the arc to the reflector, is 
4 inches, and the distance from the reflector to the aperture is 24 
inches, there being an axial magnification of 6 to 1. At an angular 
aperture of 60° from the axis there is an amount of spherical under- 
correction equal to about 250 mm or 10 inches; that is, the marginal 
rays cross the axis about ten inches in front of the aperture. This 
accounts for the extremely hazy and diffused spot on the cooling 
plate when spherical reflectors of such large angular aperture are 
employed. The spherical under correction in this reflector is so great 
that the marginal portions are in reality of no value whatever — even 
when used with the highest speed projection lens — a 5 inch Series II 
working at a speed of f/2.0. If a screen be placed a few inches ahead 
of the projection lens, and the image of the reflector, as formed by the 

^ 220 mm 

618 mm 

Fig. 1 
Showing spherical aberration (under corrected), in millimeters, for zones 
up to 60° from the axis for a spherical reflector, having two parallel spherical 
curves; the focal length of the reflector being such that there is an axial mag- 
nification of the source of 6 to 1^ the working distance of the source being 
103 mm. 

projection lens, is observed, it will be seen that a portion of the 
reflector equivalent to about 6-3/4 inches diameter is illuminated and 
being used when the source employed is very small, a five ampere arc, 
for instance. The remaining portion of the reflector from 6-3/4 inches 
diameter and greater is dark and not functioning. 

As shown in Fig. lA, due to the high spherical under-correction 
of the reflector, the rays of light from the marginal zone are unable to 
pass through the film aperture to the projection lens. In other 
words, the reflector is functioning usefully only through an angular 
aperture of about 45° from the axis, corresponding to a diameter of 
6-3/4 inches and indicating that with a spherical reflector of this 
sort, 150 mm or 6 inches of spherical under-correction represents 
just about the maximum, let us say under-corrected illumination, 
that can be made to pass through the film aperture to the projection 


Transactions of S.M.P.E., January 1926 

lens. This means that a spherical reflector of 6-^ inches diameter 
having a working distance of 4 inches and an axial magnification of 6 
will deliver to the screen nearly as much light as will the same reflector 
8 inches in diameter when small light sources are used. As a matter 
of fact, this same reflector is supplied to the motion picture trade in a 
diameter of 6-5/8 inches. You will note that we have said that the 
6-% inch diameter reflector will deliver almost as much light as the 
8 inch diameter reflector. In actual practice, however, the 8 inch 
diameter reflector will deliver somewhat more light for the reason 
that the marginal zones of the reflector will also usefully image 
portions of the crater off the axis when sources as large as say a 
25 ampere arc are used, whereas we have been considering only the 
imaging of a point on the axis. 

Fig. 1A 
Showing crossing points and position of rays from zones 20°, 40°, and 
60° for the reflector shown in Figure 1. Note the large diffuse spot due to 
zone at 60°. 

We may mention at this point also that this apparent "bunch- 
ing" of the rays from the marginal zones produces greater illumination 
on the optical axis than at points removed from the axis, resulting 
in screen illumination which is brighter in the center than at the 

The Combination of Parabolic Reflector and Condenser 

A parabolic surface is generated by the rotation of a parabola 
about its axis and is free from spherical aberration for an object or 
image in two points, its focal point and infinity. 

In Fig. 2 is shown the spherical under- correction of a combination 
of parabolic reflector and condenser for zones up to 60° from the 
axis. Reflector and condenser each have a diameter of 8 inches, the 

Reflector Arc Projection — Stark 


working distance of the arc being about 3-^^ inches. The focal 
length of the unit is such that there is an axial magnification of 6 to 1. 
It will be seen that there is spherical under-correction of about 
80 mm or a little over 3 inches in the 60° zone. This is a great im- 
provement over the spherical reflector having a spherical under- 
correction of 10 inches in this zone. This spherical under-correction 
is due only to the condenser as the parabolic reflector is free from 
spherical aberration for an object in its focal point. It is possible to 
correct this unit further by employing a parabolic correcting surface 
on the condenser. The general performance of the system would not 
be improved sufficiently to warrant the introduction of an aspheric 





Fig. 2 
Showing spherical aberration (under corrected), in millimeters, for zones 
up to 60° from the axis for a combination of parabolic reflector and simple 
piano convex condenser; the focal length of the unit being such that there is 
an axial magnification of the source of 6 to 1, tlie working distance of the 
source being 86 mm. 

With this unit, the spot on the cooling plate is fairly sharp, 
not diffused as in the case of the spherical reflector. The screen 
illumination is much more uniform and much greater than with the 
spherical reflector. If a screen be placed a few inches in front of the 
projection lens, it will be found that the whole of the reflector is 
brightly illuminated and functioning usefully, so that in spite of the 
80 mm of spherical under-correction, light from the marginal portions 
of the reflector still passes through the film aperture into the pro- 
jection lens, utilizing an angular aperture of 60° from the axis. 

Combination of Mangin Mirror and Condenser 

A Mangin mirror is a reflector in which the spherical aberration 
has been reduced to a minimum by the proper choice of two spherical 
curves. In the general use of the term it is spherically corrected 


Transactions of S.M.P.E., January 1926 

for its focal point and infinity. The Mangin mirror or lens mirror 
was invented in the late 80's by Captain Mangin, a French Army 
Engineer. It is really a combination of a spherical reflector and a 
negative lens which neutralizes the spherical aberration of the 
reflector. It was designed as a substitute for a parabolic mirror. 

Although ordinarily in the strictest sense of the word an optical 
system with a few exceptions, can be spherically corrected for 
two zones only — axis and margin or axis and some intermediate 
zone — we can, however, distribute the proportion of under-corrected 
and over-corrected zones in such a manner that under any specified 
condition the system performs the best it possibly can. It is in 
this sense that we shall use the term "spherically corrected." When 
we say that a Mangin mirror is spherically corrected for an object 
in its focal point, we shall mean that with the restrictions placed 
upon it such as spherical surfaces, diameter, magnification, etc, 
it has the best possible spherical correction, and not necessarily 
that the crossing points for axis and margin coincide. 

(J) 200 mm 
^ 8" 
















' 33A" ^^ 

40 40 men 






Fig. 3 
Showing spherical aberration in millimeters, for zones up to 60° from the 
axis for a combination of a Mangin mirror corrected for its focal point and 
infinity and a simple piano convex condenser; the focal length of the unit 
being such that there is an axial magnification of 6 to Ij the working distance 
of the source being 92 mm. 

In Fig. 3 is shown a combination of such a Mangin mirror and 
condenser. The diameter of both Mangin mirror and condenser is 
8 inches, the working distance of the reflector being about Z-% inches. 
The focal length of the unit is such that there is an axial magnification 
of 6 to 1. From a study of this curve it is evident that this is a very well 
corrected system, there being a maximum spherical over-correction 
of about 30 mm in the 60° zone and a maximum spherical under- 
correction of about 40 mm in the 40° zone. This system which is 
partially over-corrected and partially under-corrected is the result of 
combining the marginal spherical over -correction of the Mangin 

Reflector Arc Projection — Stark 101 

mirror with the spherical under-correction of the condenser and 
represents a better spherical correction than the combination of 
parabolic reflector and condenser in which the spherical aberration 
is all under-corrected. If the image of this reflector be observed on a 
screen placed a few inches in front of the projection lens, we shall 
find, as in the previous case of parabolic reflector and condenser, that 
the whole of the reflector is illuminated and being used up to an 
angular aperture of 60° from the axis. 

The spot on the cooling plate will be just a little sharper and 
the screen illumination just a little more uniform than it is with 
the parabolic reflector and condenser. . The screen illumination 
although greater than that obtainable with an ordinary spherical 
reflector will be less than that of the parabolic reflector combined 
with a condenser due to the loss of light by absorption in the double 
passage through such a thick reflector. Due to the shape and size, 
it is necessary in order to prevent excessive breakage to make this 
reflector of heat resisting glass. 

Pig. 4 
Showing spherical aberration (over corrected), in millimeters, for zones 
up to 60° from the axis for a parabolic reflector, having two parallel para- 
bolic curves when used for finite imagery; the focal length of the reflector 
being such that there is an axial magnification of 6 to 1, the working distance 
of the source being 98 mm. 

Parabolic Mirror used for Finite Imagery 

In Fig. 4 is shown a curve representing the spherical over- 
correction of a parabolic reflector when used without a condenser in 
imaging an object at a finite distance. This reflector has a diameter of 
8 inches and a working distance of about 4 inches. The focal length 
is such that the axial magnification is 6 to 1. The spherical over- 
correction of a reflector of this sort used in this way amounts to 
500 mm or 20 inches. It may appear at first glance that this system is 
much inferior to the ordinary spherical reflector having a spherical 

102 Transactions of S.M.P.E., January 1926 

under-correction of 250 mm or 10 inches. As a matter of fact, the 
500 mm of over- correction in the paraboHc reflector used for finite 
imagery just about corresponds to 250 mm of under-correction of the 
spherical reflector as far as optical quality of imagery is concerned. 
The reflector here illustrated is hardly superior to the spherical 
reflector. If the image of the reflector, as formed by the projection 
lens is examined on a screen, it will be found that only the portion 
of the reflector equivalent to an angular aperture of 45° to 50° from 
the axis functions usefully; that is, puts light through the aperture 
into the projection lens, the remainder of the reflector being dark 
when small light sources are used. The spot on the cooling plate will 
be sharper than when the spherical reflector is used, although not as 
sharp as with the combination of either parabolic reflector or Mangin 
mirror with condenser. The quantity of light projected upon the 

6 200 mm 

Fig. 5 

Showing spherical aberration in millimeters for zones up to 60" from the 

axis for a Mangin mirror corrected for infinity and its focal pointy when used 

for finite imagery; the focal length of the reflector being such that there is an 

axial magnification of 6 to 1, the working distance of the source being 103 mm. 

screen will be about the same as with the spherical reflector, the even- 
ness or uniformity of illumination being better. This latter is due to 
the fact that the spherical over -correction of the reflector counteracts 
to some extent the fact that the center of the arc crater is brighter 
than the portions nearer the rim with the result that more light is 
thrown to the margins of the field than otherwise would be the case. 

Mangin Mirror used for Finite Imagery 

In Fig. 5 is shown the spherical aberration in a Mangin mirror 
corrected for an object in its focal point when used for finite imagery. 
The diameter of the reflector is 8 inches, working distance 4 inches, 
and focal length such that the axial magnification is 6 to 1. There 
is a spherical over-correction of about 70 mm in the 60° zone and a 

Reflector Arc Projection — Stark 103 

spherical under-correction of about 30 mm in the 40° zone. This is 
a fairly well corrected system even when used for imaging an object 
not in its focal point. The spherical correction is not as good, however, 
as when it is combined with a condenser, although it is better than 
the spherical correction in the combination of parabolic reflector and 
condenser and, of course, far superior to the spherical reflector or 
parabolic reflector when used without condenser. The image of the 
whole reflector as formed on a screen placed a few inches in front 
of the projection lens is brightly illuminated, indicating that as far 
out as the 60° zone light passes through the film aperture to the 
projection lens. The screen illumination is even, although not as 
uniform as when the Mangin mirror is used in combination with a. 
condenser. The uniformity of illumination is slightly better than the 
combination of parabolic reflector and condenser and far superior 
to the spherical reflector or paraboUc reflector without condenser. 
The spot on the cooling plate is very well defined, not quite as sharp, 
however, as the combination of Mangin mirror with condenser, but 
slightly sharper than the combination of parabolic reflector with 
condenser, and far better than the spherical reflector or parabohc 
reflector without condenser. The quantity of light projected to the 
screen by this reflector will be slightly more than that projected by the 
combination of Mangin mirror and condenser, considerably more than 
that projected by either the spherical reflector or parabolic reflector 
without condenser, but less than that due to the combination of 
parabolic reflector and condenser. This is due to the absorption 
which occurs when the light passes through such a thick reflector 
twice. Due to the size and shape, the reflector must be made of heat 
resisting glass to prevent excessive breakage. 

The Modified Mangin Mirror 

In Fig. 6 is shown a curve representing the spherical aberration 
of a reflector which we have called a modified Mangin mirror, because 
it is spherically corrected for an object not in its focal point, a true 
Mangin mirror being corrected for an object in its focal point. The 
diameter of this reflector -is 155 mm or 6-M inches. The working 
distance is 80 mm or about 3-J4 inches. The focal length is such 
that the axial magnification is 7 to 1, instead of 6 to 1, as is the case 
with the reflecting systems so far described. It was found necessary 
from a manufacturing standpoint to reduce both diameter and work- 
ing distance and to slightly increase magnification, because the size 

104 Transactions of S.M.P.E., January 1926 

and shape was such that the reflector became impossible of con- 
struction if large diameter and working distance were maintained 
and the reflector constructed to take in a cone of light 60° from the 

It is evident that the spherical correction of this reflector is 
excellent and illustrates very nicely what can be done along these 
lines by proper choice of two spherical curves: the maximum under- 
correction is only 15 mm in the 40° zone, the maximum over-correc- 
tion being 40 mm in the 60° zone. The whole of the reflector functions 
usefully through an angular aperture 60° from the axis. The spot 
on the cooling plate is more sharply defined than with any of the 
systems so far mentioned. The screen illumination is more uniform 
than with any of the systems so far described with the exception 
possibly of the combination of Mangin mirror with condenser. The 
quantity of illumination although greater than that obtainable with 

t 155 mm 
6 'A" 

Fig. 6 

Showing spherical aberration, in millimeters, for zones to 60° from the 
axis for a reflector corrected for finite object and image distances by suitable 
choice of two spherical curves ; the focal length of the reflector being such 
that there is an axial magnification of approximately 7 to 1, the working 
distance of the source being 80 mm. 

a spherical reflector, a parabolic reflector without condenser, and 
possibly with a Mangin mirror in combination with a condenser, is 
not as great as that obtainable with the combination of parabolic 
reflector and condenser or Mangin mirror alone. Due to the shape 
and size of the reflector, it is necessary to construct it of heat resisting 
glass in order to prevent excessive breakage. 

The Elliptical Reflector 

It seems that since the advent of the Reflector Arc in motion 
picture projection, the standard of screen quality or uniformity of 
illumination has fallen considerably. Whereas, previously, we were 
very critical and exacting in having the screen evenly illuminated, 
we now seem to tolerate a screen with a center considerably and 

Reflector Arc Projection — Stark 105 

noticeably brighter than the edges. The enormously decreased cost 
of operation has pushed into the background the idea of quality of 
illumination. It is very true that an ordinary spherical reflector 
will produce a brighter central illumination on the screen than will, 
let us say, for example, a modified Mangin. But a modified Mangin 
mirror produces an evenly illuminated screen which a spherical re- 
flector, by the very nature of its optical defects cannot possibly do. 
In spite of this, a spherical reflector is often chosen in preference to 
another type because, since the center of the screen is bright, one has 
the impression of more light on the screen. 

It has been our experience that any reflecting arc system em- 
ployed with, say a 25 ampere arc, should have an axial magnification 
of 6 to 1. The average useable crater diameter of a 20 to 25 ampere 
horizontal carbon arc is between 5 and 6 mm. A magnification of 6 to 
1 will image this as a 30 to 36 mm arc image, which is just large enough 
to cover the film aperture nicely. 

The highest speed projection lens, a 5 inch Series II, will pass 
a cone of light slightly over 10° from the axis; that is, a cone of 
light whose total angular diameter is 20°. This immediately makes 
it useless to employ illuminating angles of more than 10° from the 
axis. If the magnification is 6 to 1, then the total angular aperture 
of the reflector must be 6 times 20° or 120°. In other words, the 
reflector must take in a cone of light 60° from the axis. It is valueless 
to take in more, if the magnification is 6 to 1, because the illuminating 
cone will then be larger than 20°, the limiting angle for the highest 
speed projection lens. Thus, when the magnification is fixed or 
determined (we recommend 6 to 1 magnification) and the maximum 
illuminating cone is known (20°), the maximum useable angular 
aperture of the reflector is immediately fixed (120°). For very low 
amperage arcs, such as 5 or 10 amperes, where the useable portion 
of the crater is less than 5 mm in diameter and where it becomes 
necessary to use a larger magnification, say 7 to 1, in order to cover 
the film aperture, then the angular aperture of the reflector can 
usefully be increased to 70° from the axis or 140°. Most reflector 
arcs, however, are used with arcs of 20 to 25 amperes where a magni- 
fication of 6 to 1 is sufficient. 

Always keeping in mind that the reflector should have a total 
angular aperture of 120°, it is advisable to have a reflector of as large 
a diameter as possible in order that the shadow or projected area of 
the positive carbon and its supporting mechanism should cut off as 

106 Transactions of S.M.P.E., January 1926 

low a percentage of the useable reflector area as possible. However, 
the mechanical limitations of lamphouse mounting, etc., permit of a 
maximum distance between reflector and aperture of only about 
25 inches. If we assume this distance of reflector to aperture to be 
24 inches and also assume a magnification of 6 to 1, then the working 
distance of the arc is immediately determined as 4 inches, (24 i aches 
divided by 6). Thus, knowing the required working distance to be 
4 inches and the required total angular aperture to be 120°, the 
necessary diameter, 8 inches, of the reflector also follows. Finally, 
we may sum up the requirements of an ideal reflector to be (1) total 
angular aperture 120°, (2) total illuminating cone 20°, (3) magnifi- 
cation 6 to 1, (4) working distance 4 inches, (5) distance of reflector 
to aperture 24 inches, and (6) diameter of reflector 8 inches. 

<}) 200 mm 





Fig. 7 

Showing complete spherical correction in all zones, for an elliptical re- 
flector, having an axial magnification of 6 to 1, and a working distance of 
100 mm. 

Having in mind these ideal requirements, more or less of a 
mechanical nature, in Fig. 7 is shown the spherical aberration of an 
elliptical reflector, 8 inches in diameter, having a working distance of 
4 inches and an angular aperture of 60° from the axis. The distance 
from reflector to aperture is 24 inches and the axial magnification, 
6 to 1. There is no spherical aberration whatever in this reflector. 
The whole of the angular aperture of this reflector functions usefully. 
The spot on the cooling plate is sharper than with any of the reflector 
systems previously mentioned, and the screen illumination is greater 
and more uniform than with any of the other systems. The shape 
of the reflector is such that the projection angle can be as great as 
30° before the arc flame touches the edge of the reflector. 

An elliptical reflector or rather an elliptical surface is generated 
by the rotation of an ellipse about its major axis. Such a reflector 

Reflector Arc Projection— Stark 


is free from spherical aberration for an object or image in either of its 
geometrical foci. The equation of this particular generating ellipse is 

X2 y2 
+ =1 

3502 2452 

The major axis of the ellipse is 700 mm, the minor axis 490 mm; 
the geometrical focus being 100 mm. 

The following is a seK explanatory table in which is listed in 
order of best to worst the seven reflecting systems discussed in respect 
to practicabihty, definition of spot on cooling plate, uniformity of 
screen illumination, quantity of screen ilkunination, and spherical 

Table showing the order into which the various reflecting systems fall 

in regard to practicabihty, definition of spot on cooling plate, 

uniformity of screen illumination, quantity of screen 

illumination and spherical aberration. 



D efinition 






















Mangin with 

Mangin with 

Mangin with- 
out Condenser 

Mangin with 






































Mangin with 





Under practicability we include those questions relating to 

108 Transactions of S.M.P.E., January 1926 

initial cost and subsequent cost of replacement due to breakage, and 
the general ease of mechanical manipulation. 

The following is a bibliography of foreign articles on reflector 
arc projection, there being practically nothing of any importance 
in English journals on this particular subject. 

Investigations Concerning Illumination on the Cinematographic Projector 

Zeitschrift fur Technische Physik, 1923, No. 10. p. 329. 

Die Kinotechnik, Nr. 1/2, 1924. 

Condenser Lamp, Reflector La7np, and Fire Protection of the Projector 

M. Flinker, Die Kinotechnik, 6, p. 13, 1924. 

The Different Forms of Reflecting Mirrors Available for Projecting Lamps 

C. Forch, Die Kinotechnik, 6, p. 31, 1924. 

The Effect of Cooling Chambers With Reflector Arc Lamps 

H. Joachim & H. Schoenig. Die Kinotechnik, 6, p. 91, 1924. 

Shadow-Free Slide Projection With Stationary Lamp House and the Use of Reflector 

M. Adam, Die Kinotechnik, 6, 20, p. 373, 1924. 

Comparative Brightness and T erjiperature Measurements on Reflector Arc Lamps 
Dr. Joachim & Dr. Noack, Die Kinotechnik, 5, 7, p. 175, 1923. 
Comparison of the Danger of Film Burning with Condenser and Reflector Lamp 
C. Forch, Die Kinotechnik, 5, 19/20, p. 457, 1923. 
Reflector Lamp with Shadow-Free Slide Projection Arrangement 
W. Winsenburg, Die Kinotechnik, 5, 21/22, p. 491, 1923. 

Objectives With Large Aperture for Motion Picture Projectors with Mirror Arcs 
M. Adam, Die Kinotechnik, 6, Aug. 25, 1924, p. 269. 
Light Intensity Measurements on Projector Arcs 
M. Flinker, Die Kinotechnik, 6, July 25, 1924, p. 221. 
Photo Technical Investigations on the Cinematographic Projector 
Meinel, Phot. Ind., May 30, 1923, p.' 259. 


Mr. Benford: In one slide Mr. Stark showed a combination o 
a parabolic mirror and a condenser with under-correction. One 
optical fact of importance is that if the light source is moved toward 
the mirror, the light rays will diverge, and the divergence is an 
angular maximum at 60°. I think that combination could be made 
almost exact optically by moving the light source toward the center 
of the mirror. Also, all the light reflected from the front surface of 
the Mangin mirror does not form a focus spot. There is a loss of 5 
per cent which does not take place in the other combinations. 

Reflector Arc Projection — Stark 109 

I do not believe that it is an exact rule that the angular apertures 
of objective and condenser have a fixed ratio regardless of the nature 
of the condenser. The angular opening of a paraboloid will be less 
than that of an elhpsoid, and the other forms will each have a different 
collecting angle. 

Mr. Egeler: Mr. Stark showed several systems using non- 
spherical glass surfaces and listed them in the order of practicability. 
Are all the systems practical from the standpoint of the present art 
of optical manufacture? 

Mr. Richardson: Cannot the ordinary reflector be changed 
to eliminate spherical aberration without thickening the edge? 

Mr. Palmer: In regard to the elliptical reflector, that seems 
to be the best type of reflector from Mr. Stark's description: How 
much loss in efficiency do you get by a slight displacement from the 
proper focus of the mirror? It could not be expected that the mech- 
anism would always be operated under theoretically correct condi- 
tions, and I should like to know the loss in efficiency due to displace- 
ment from the theoretically correct position. 

Mr. Griffin: What is the relative cost of the various systems 

Mr. Gray: It would seem to me as if the question of high spot 
temperature encountered with mirror arc projection is a problem in 
the field. I was wondering whether in any of the systems mentioned, 
considering equal screen results with any two, whether the difference 
in temperature might not be considerable. 

Mr. Stark: Mr. Benford's suggestion of moving the source 
towards the reflector, in the combination of parabolic reflector and 
condenser, in order to decrease the residual spherical aberration of 
the combination, is very much to the point except that the source 
should be moved away from the reflector instead of toward it. 
A parabolic reflector and condenser is spherically under-corrected, 
as shown in Fig. 2. The problem, then, is to introduce spherical 
over-correction in some way in order to counteract the spherical 
under-correction of the condenser alone — which under-correction is 
actually the residual aberration of the combination. If the source is 
moved toward the reflector from the focal point, the beam of light 
as a whole is diverging, the image formed is virtual and under- 
corrected, and the combination with the under-corrected condenser 
becomes still more under-corrected. If, however, the source is 
moved away from the reflector from the position of the focal point, 

no Transactions of S.M.P.E., January 1926 

the beam of light is converging, the image, formed at a finite distance, 
is real and over- corrected, and the combination with the under- 
corrected condenser will be more nearly corrected, obviously, if the 
over-correction introduced is not too great. 

It is true that in any of the Mangin combinations there is a loss 
of approximately 4 per cent at the first surface which does not 
occur with reflectors having parallel surfaces. 

It is not true, strictly speaking, that the ratio of the angular 
aperture of the reflector to the angle of the illuminating cone is the 
axial magnification of the system. For the purposes here considered 
it is, however, a simple and satisfactory approximation. In Gaussian 
optics, where only aberrationless systems having very small angular 
apertures, such that only the paraxial region need be considered, the 
magnification is represented by the ratio of the tangents of haK the 
angular aperture of the reflector to half the angle of the illuminating 
cone. In systems of large angular aperture, the magnification for a 
corrected system is represented by the ratio of the sines of half the 
angular aperture of the reflector to half the angle of the illuminating 
cone. The particular magnitudes with which w^e are dealing in this 
problem are such that the ratio of the angular aperture of the reflector 
to the angular aperture of the illuminating cone is very nearly equal 
to the ratio of the sines of half these angles respectively — and we have 
consequently used this method of expressing it on account of its 

Answering Mr. Egeler's question regarding the practicability 
of the manufacture of non-spherical optical units, I should say that 
it is practicable at the present time to manufacture on a commercial 
basis and of an optical quality suitable for motion picture illuminating 
systems both parabolic and elliptical reflectors. Not so long ago, 
it would certainly have been impracticable to do this. Recently, 
however, there has been considerable experimental work conducted 
in just this particular field with the result that methods of manu- 
facture have been developed whereby the production of elliptical 
reflectors of good optical quality, on a commercial basis, and within 
reasonable cost, has been accomplished. 

Mr. Richardson's suggestion of decreasing the spherical under- 
correction of the spherical reflector shown in Fig. 1 by moving the 
source nearer to the reflector is not a solution to the problem. If 
the source were moved in such a way, the axial image would move 
away from the reflector at a proportionally increasing rate until 

Reflector Arc Projection — Stark 111 

when the source is in the focal point of the reflector, the axial image 
would be at infinity and the marginal unage at some finite distance 
from the reflector (the margin being under-corrected). Moving 
the source toward the reflector would result in increasing the spherical 
aberration instead of decreasing it. On the other hand, if the source 
were moved away from the reflector, the spherical aberration would 
progressively decrease until, when the source is in the center of 
curvature of the reflector, the spherical aberration w^ould become 
zero — the spherical reflector being spherically corrected for object 
and image in its center of curvature. 

If the spherical reflector shown in Fig. 1 were to be distorted in 
such a manner that spherical aberration were reduced to zero — 
the imager^" being effected by reflection only — the resulting surface 
would be the ellipse shown in Fig. 7. We can, on the other hand, 
restrict ourselves to the use of two spherical surfaces, and by suitable 
choice of the radii of curvature of these two spherical surfaces effect 
spherical correction by a combination of reflection and refraction, 
as in the case of a Mangin mirror. The best that can be accomplished 
in this direction is to reduce the spherical aberration to a minimum 
by properly balancing the residual zonal under-correction with 
marginal over-correction. For a specified focal length or working 
distance and a specified magnification, there is just one combination 
of two spherical curves that give such spherical correction, and these 
curves always result in a reflector which is thick at the margin. 

Regarding Mr. Palmer's inquiry concerning the accuracy with 
which it is necessary to hold the source in the geometrical focus 
of the eUipse — this is more or less diflB.cult to answer. Certainly, 
the best results will be obtained if the source is maintained accurately 
in the proper position. If the source is nearer the reflector than its 
geometrical focus, the reflector will be under-corrected for this 
increased magnification; while if the source is further from the 
reflector than its geometrical focus, the reflector wiU be over-corrected 
for this decreased magnification. The amount of over -correction or 
under- correction will be greater or less as the source is further 
removed from its correct position. I do not beheve that the question 
of accurate positioning of source should occasion any alarm, as the 
modern construction of reflecting arc lamp houses is such that the 
positive crater can be held in its proper position within exceedingly 
small limits. 

I must confess to Mr. Griffin that I am not intimately acquainted 

112 Transactions of S.M.P.E., January 1926 

with the cost or prices of the various systems described. It would 
seem reasonable to suppose that the spherical reflector is the cheapest. 
The parabolic reflector of commercial quality costs somewhat more. 
Possibly the elliptical reflector would cost as much as the combination 
of parabolic reflector and condenser. The reflectors of the Mangin 
type all cost considerably more than the spherical reflector — which 
is the reason I place them in the lower positions in the table of 

Mr. Gray's question of temperature at the film gate brings up 
a problem on which we have done no experimental work whatever. It 
is without argument, I believe, that the temperature at the cooling 
plate will be approximately the same for any of the systems described. 
No radical difterences in temperature are to be expected. All the 
systems shown have the same angular aperture and the same magni- 
fication, and if due allowances are made for the heat absorption 
of the condenser in the combination of parabolic reflector and con- 
denser, as well as for the heat absorption in the Mangin types, the 
temperatures should all be about the same. It would also be reason- 
able to expect a slight increase in temperature in the better corrected 
systems due to the fact that the spot on the cooling plate is more 
sharply defined. I might refer Mr. Gray to a few of the papers listed 
in the appended bibliography. 

Mr. Griffin: What result will the elliptical mirror have if 
used on the arc lamps already under construction? We happen to be 
making one with which we project lantern slides with the same 
optical system. I suppose this can be done with an ellipse and would 
not necessitate radical changes in design. How soon will the elliptical 
mirrors be available? 

Mr. Little: In reference to Mr. Palmer's question in regard 
to the necessity for accurate focusing, a general statement might 
be made to the effect that any reflector formed by the revolution 
of conic sections of equal focal length are equally sensitive; therefore, 
the sensitivity of a reflector of this character is directly proportional 
to the focal length. That is, the longer the focus, the less the sensitiv- 

Mr. Kunzman: Are the mirrors manufactured to definite crater 
diameters for a given amperage and carbon combination? 

Mr. Beggs: I should Hke to know how ellipses versus Mangin 
would compare when made of heat resisting glass? 
. -Mr. Stark: Without having given the problem any previous 

Reflector Arc Projection — Stark 113 

thought, it would seem that if an auxihary prism with condenser 
or decentered condenser alone were to be placed near the elhptical 
reflector, lantern slides could be projected if the slides were sufficiently 
near the auxiliary system to be fully illuminated. 

Mr. Griffin: The carbon is there and is 8 inches long, so that 
there would be 10 inches or 12 inches of obstruction. 

Mr. Stark: Could not the slides be projected in the same 
manner in which it is now accomplished with a spherical reflector? 

Mr. Griffin: By moving the spherical reflector, you get a 
parallel beam, and at a point where the beam becomes parallel, about 
16 inches from the outer surface of the mirror, we insert a 20 inch 
condenser. The sHde is placed close to the condenser, and it works 
out well. 

Mr. Stark: Exactly the same method can be employed with an 
elliptical reflector and with better results. The group of conic 
sections includes the circle, ellipse, parabola and hyperbola. The 
surfaces of revolution of the first three curves are the ones generally 
used in optical practice. The sphere is free from spherical aberration 
for an object in its center of curvature and is badly under-corrected 
for an object in its focal point, — in which position of object an 
approximately parallel beam is obtained. A parabolic reflector is 
free from spherical aberration for an object in its focal point, in 
which position of object a parallel beam is obtained. An ellipse is 
midway between the parabola and sphere, and consequently, with an 
object in its focal point the resulting parallel beam, although not as 
perfect as that of a parabola, is better than the parallel beam obtain- 
able from a sphere. I do not know definitely as yet just when we 
shall be in a position to place elliptical reflectors on the market. 

Mr. Little's statement is correct — the longer the focal length of a 
reflector, the less effect will a given displacement of source have on 
optical performance. A displacement from correct position of the 
source with respect to a reflector might be disastrous with a reflector 
of short focal length and with no noticeable effect whatever with a 
reflector of greater focal length. 

Mr. Kunzman's question relating to the crater diameter for 
which the reflectors were designed: I would say that for all of the 
reflectors discussed, we have assumed the crater diameter of a 
20 to 25 ampere horizontal carbon arc, this being in the neighborhood 
of 5 to 6 mm. 

114 Transactions of S.M.P.E., January 1926 

In answer to Mr. Beggs— in view of the great thickness of glass 
at the margin of the reflector, it is necessary in order to prevent 
excessive breakage to construct all Mangin types of reflectors from 
heat resisting glass. With the thinner types — such as the spherical, 
paraboHc and elliptical reflectors — ordinary optical glass well 
annealed is entirely satisfactory. 








Officers, Committees 3-4 

Report of Standards and Nomenclature Committee 5 

Report of Proceedings of International Congress of Pho- 
tography, Section IV, Cinematography. By L. P. 

Clerc 29 

The Questionable Educational Value of Motion Pictures. 

By A. W. Abrams 50 

Movies for Teaching; the Proof of their Usefulness. By 

Rowland Rogers 66 

The High Intensity Arc. By Frank Benf ord 71 

Rack Marks and Airbell Markings on Motion Picture Film. 

By J. I. Crabtree and C. E. Ives 95 

A High Power SpotUght Using a Mazda Lamp as a Light 

Source. By L. C. Porter and A. C. Roy 113 

The Effect of Scratches and Cuts on the Strength of Motion 

Picture Fihn. By S. E. Sheppard and S. S. Sweet 122 

Importance of Proper SpMcing. By E. J. Denison 131 

The Pathex Camera and Projector. By W. R. Daniel 147 

Color Photography Patents. By W. V. D. Kelley 149 

Obituary of Dr. Kellner 162 

Advertisements 163 

Number Twenty-four 

MEETING OF OCTOBER 3, 6, 7, 8, 1925 




r=^ i =11 >i 'r= 'P= i f^^=^ i ^ r=ir 








Number Twenty-Jour 

MEETING OF OCTOBER 5, 6, 7, 8, 1925 


" II ■ '= i f= I I — i n 


• ^3 

' ^3 

Copyright, 1926, by 

Society of 

Motion Picture Engineers 

New York, N. Y. 


Engineering Societies Building 
29 West 39th St., New York, N. Y. 

Papers or abstracts may be reprinted if credit is given to the Society of 
Motion Picture Engineers. 

The Society is not responsible for the statements of its individual members. 


APR -576 

-x \ 



P. M. Abbott 

J. A. Summers 



Past President 
L. A. Jones 

Board of Governors 
W. B. Cook 
L. A. Jones 
W. C. Hubbard 
J. A. Summers 
J. H. McNabb 
F. F. Renwick 
Raymond S. Peck 
J. H. Theiss 
J. A. Ball 

M. W. Palmer 

W. C. Hubbard 

J. I. Crabtree 

L. C. Porter 

F. H Richardson 

J. C. Kroesen 

J. C. Kroesen 

Geo. A. Blair 

L. C. Porter 

J. C. Kroesen 
R. S. Peck 



C. E. Egeler, Chairman 
Rowland Rogers 
W. V. D. Kelley 

Standards and Nomenclature 
J. G. Jones, Chairman 
H. P. Gage 
C. M. Williamson 

P. M. Abbott, Chairman 
Geo. A. Blair 
R. S. Peck 

Wm. F. Little, Chairman 

J. C. Hornstein, Chairman 
J. C. Kroesen 
P. M. Abbott 

J. I. Crabtree, Chairman 
C. E. Egeler 

A. C. Dick, Chairman 
F. H. Richardson 
Earl J. Denison 

Kenneth Hickman 

C. A. Ziebarth 
Herbert Griffin 

F, H. Richardson 

J. A. Summers 

W. V. D. Kelley 

L. A. Jones 

Wm. C. Kunzman 


A COMPLETE list of the standards and nomenclature in effect 
October 1, 1925, has been prepared and included with Volume 
No. 2 of the Schenectady Transactions. 

The Committee again recommended the final adoption of the 
matters presented at Schenectady, last May, as follows: 

(1) Perforation of positive fihn — a rectangular hole 1 .98 x 2.79mm 
with rounded corners 

(2) Aperture Sizes. — 

Camera: 0.700'Vhigh x 0.925" wide; 0.035'' radius corners 
Printer: 0.757" high x 1.000" wide; 3/64" radius corners 
Projector: Already standardized as 0.725" high x 0.950" wide; 

square corners 
N.B. Camera aperture corners may be either square or rounded, 
but the projector aperture corners must be square. These sizes pro- 
duce the black border. 

(3) Projector Speed — 80' per minute, plus or minus 5 

(4) Camera Speed — 60' per minute, plus or minus 5 

(5) External diameter of projection lens barrels — 

No. 1 lenses, 2 1/32", No. 2 lenses, 2 25/32" 

(6) Tolerances on dimensions of films — None 

(7) Definition of ''Scene^^ 

"A division of the story showing continuous action in the same 
locale or set, and usually taken from the same point of view." 

(8) Definition of '' Reflector Arc'' — 

"In a motion picture projector, an arc light source in combination 
with a reflector, to project the hght beam through the aperture." 

All of the above matters have stood the required six months, were 
given the final approval by the Society, and thereby become officially 

The following matters were referred back to the Committee for 
further consideration : 

(9) Recommended practice for film splicing 

6 ■ Transactions of S.M.P.E., March 1926 

(10) Dimensions of Camera Reel Cores 

(11) Dimensions of Sprockets 

A report of the Sixth International Congress of Photography, 
recently held in Paris, was given together with the actions which 
were taken there. * 

October, 1925. L. C. Porter, 

Chairman, Standards and Nomenclature Committee. 



You will recall that action on most of the matters presented in 
our report at Schenectady, last May, was deferred out of deference 
to the Paris Convention. Unfortunately, neither of the men you 
appointed to officially represent the Society, i.e., Messrs. Mees and 
Renwick, finally attended the convention. However, Dr. Sheppard 
of the Eastman Kodak Company was there and took the responsibil- 
ity of representing the Society of Motion Picture Engineers at the 
International Congress. That Congress decided to accept our policy 
of six months' delay (reckoning from July, 1925) before their actions 
become final. This gives us time to enter any comments or objections 
before the actions taken by the Congress are adopted. 

The co-ordination of any oppositions that may arise was put in 
charge of the following committee: 

Germany, Prof. Lehmann; France, L. Lobel; Great Britain, a 
delegate to be appointed by the Cinematographers Manufacturers 
Association; Czecko-slovakia, C. J. Brichta; United States, a delegate 
to be appointed by the Society of Motion Picture Engineers. 

Mr. L. Lobel was appointed Secretary to this Committee. 

In the event of a lack of agreement through correspondence 
between the members of the executive committee, at the expiration 
of the time fixed above, these members shall meet in Paris on a 
suitable date to formulate the definite resolutions. 

Your Committee has studied carefully the official report of the 
Sixth International Congress of Photography held at Paris last June. 
While we do not find any actions taken at this Congress that would 
make it seem desirable to change our recommendations of last May, 
still we feel that the proceedings and discussions of so important a 
body' of men are of sufficient interest and value to warrant printing 

Report of Standards and Nomenclature Committee 7 

them in their entirety in our Transactions. We are, therefore, pre- 
senting them as a supplement to our report. 

No new matters have come to the attention of the Committee 
since last May. We are, therefore, again presenting the matters 
which were not definitely settled at Schenectady, as follows : 

1. Form of perforations for positive and negative 35 mm film 

2. Dimensions for camera and printer apertures 

3. Projector speed 

4. External diameter of No. 1 and No. 2 projection lenses 

5. Camera speed 

6. Film splicing specifications 

7. Definitions for ''Scene" and "Reflector Arc" 

8. Tolerance in dimensions of 35 mm film and shrinkage in drying 

9. Dimensions of film reel cores 
10. Sprocket design 

Realizing the difficulty anyone would have in finding out the 
exact status of our Standards and Nomenclature, due to our pro- 
longed discussions, changes, and, in the early days, diversity of com- 
mittees handling these matters, your Committee has prepared a 
complete list of all Standards, Nomenclature, and Recommended 
Practice which is officially in force, as well as matters under consider- 
ation as of October 1, 1925. The Standards and Recommended 
Practice lists are arranged according to date of official adoption. The 
Nomenclature list is arranged alphabetically. In every case the date 
of official adoption is given and also the number of the Transactions 
containing the discussion. These lists will be included in the en- 
velopes with the second volume of the Schenectady Transactions, 
so that every member of the Society will receive copies. 

We are in receipt of a letter from the American Engineering 
Standards Committee inquiring as to the status of our standards and 
offering to assist in international standardization. It is our belief that 
if final action is taken on the matters brought up last May, we shall 
be in a position to present our standards to the American Engineering 
Standards Committee, and there is little doubt that they will be ac- 
cepted and adopted by that body. 

Now, let us take up in detail the matters pending final adoption 
by the Society : 

Form of Perforation 

Your Committee has been in touch with the Enghsh, French, 
and German Societies and are advised by Mr. L. Lobel of the French 

Transactions of S.M.P.E., March 1926 

organization that they have agreed to the same form and dimensions 
of perforation for positive film which we have recommended, i.e., a 
rectangular hole 1.98 x 2.79 mm with rounded corners. (Fig. 1). 

16 % Positive & Neqa tive F/l m 

Sa petyS tandard 
28% Positives, Negative Film 



J fiioi' Radios 

CoTTlNq 9 P£RFoR/^TiN<^ 5 ITS 

Standard 55% Positive fyLM. 

Cutting <S Pcn^offATiNq Sire 

5 TANDAF(D557m iVEGA TIV£ FilM. 

I . /..^ryoT" 
CorrifiQ Size 
, /JOS" 


Cutting 6, Prff^o/fATiN<i Sire 

CoTTiiK^ S. PeifnKtmfiQ Size 


Fig. 1. - 

There seems, however, to be some feeling on the part of Pathe that 
their perforation, 3 mm long x 2 mm high, having straight top and 
bottom edges but ends formed by the arc of a circle and joined to the 

Report of Standards and Nomenclature Committee 


top and bottom by rounded corners, is better, and this may be standard- 
ized also. For negative film they also have accepted our practice of 
perforations 2.79 x 1.85 mm with rounded ends (Fig. 1). 

The action taken by the Paris Congress on this matter is as 
follows: "Form of Perforations: One shall use optionally the Kodak 
perforation, rectangle of 2 x 2.8 mm with rounded angles on a radius 
of 0.5 mm or the Pathe perforation, limited by two parallel lines 
traced 1 mm apart, and on opposite sides of a circle 3 mm in diameter, 
and rounded on a radius of 0.5 mm. 

"Common limit of two successive images at mid-distance from 
two consecutive perforations." 

This does not differentiate between positive and negative film. 
Fig. 2 shows the various forms discussed at Paris. 



/ 0073" A 



^ ; ^ 




"2" 80mm 





1.38 mm 





Fig. 2. — Table of perforations showing variations in standards. 

Note : Kodak and Pathe positive shaped holes were adopted as International 
standard for positive and negative film. 

As the use and value of other forms of perforations than the 
rectangular with rounded corners for 35 mm positive film, proposed 
at the Roscoe meeting a year ago (as shown in Fig. 1), seems doubtful, 
and as the foreign practice seems to be going also to the same per- 
foration, your Committee recommends that you now accept, for final 
standardization, this form of perforation. 

10 Transactions of S.M.P.E., March 1926 


Mr. Crabtree: Did the foreign societies recommend both those 
perforations or only the Pathe? 

Dr. Sheppard: They recommended that both the Kodak and 
Pathe positive perforations as shown at the bottom of the figure be 
recommended as official for positive film and for negative film. The 
opinion of the meeting was that positive film should have the same 
dimensions as the negative film. No official American representatives 
were present, but the point of view in favor of the existing American 
negative perforation was brought forward. However, the vote went 
in favor of identical dimensions for negative and positive film. 

Mr. Crabtree: May I ask Mr. Jones if the positive rectangular 
perforation is satisfactory for all present machinery ; the upper nega- 
tive (indicating) is only suitable for negative machinery. Why was 
it adopted for both positive and negative? 

Dr. Sheppard: With the exception of this country, identical 
perforation dimensions are acceptable for positive and negative film; 
in the other countries cameras, printing machines, and projectors 
are made with differences very slight from the recommended per- 

With regard to Mr. Crabtree 's last remark, the defining dimen- 
sions of the two positive perforations are so close that they could be 
operated on any machine. 

Mr. Richardson: I have gone to considerable trouble to get 
reports from men handling motion picture. projectors, and they may 
be presumed to know more than we do about it. They all report that 
this perforation (indicating Pathe) is the strongest, has less tendency 
to fracture, and goes through more quietly and with less strain on 
the film. 

Mr. Porter: Mr. Richardson submitted reports on a large 
number of films obtained from different projectionists, and these data 
were considered by the committee. 

Mr. Chanier: Pathe and Kodak perforations are about alike; 
there is no difference in wear and tear. 

Mr. Ziebarth: In my experience I have found that Bell and 
Howell, Pathe, and Kodak perforations would not check or tear from 
running through projection machines that were properly adjusted 
and operated. In fact, I have found long before the perforation be- 
came damaged the film was so badly scratched that it would be a 

Report of Standards and Nomenclature Committee 11 

disgrace to show it, and under poor operating conditions any one of 
the three mentioned perforations would become damaged as easily 
as the other. 

Mr. Richardson: Reel upon reel is ruined on the first run be- 
cause it has not sufficient strength in the corner of the perforation. 

Will you call attention to the fact that the adoption of the rec- 
ommendation does not prevent the use of the Pathe perforation? 

{Motion thereupon duly passed to adopt recommendation.) 

Aperture Sizes 

In regard to camera and printer apertures, your Committee 
believes it to be the consensus of opinion in the Society that the black 
border is desirable. To obtain it we recommend the following aper- 
ture sizes: 

Camera: 0.700" high x 0.925" wide; 0.035" radius corners 
Printer: 0.757" high x 1.000" wide; 3/64" radius corners 
Projector: (Already standardized as 0.725" high x 0.950" wide: 

square corners.) • 
The camera aperture corners may be either square or rounded, 
but the projector aperture corners must be square. 


Mr. Crabtree: May I ask whether anybody is printing film so 
that it will have a black border? 

Mr. John Jones: We made films similar to those used abroad 
and showed them before the Society to prove the advantage, and it 
was unanimously voted that the black border film gave a steadier 
appearing picture. We propose to standardize this even if it is not 
used. The camera apertures should be smaller in order to show a 
black border. If you do not adopt it, all right; but if you do adopt it, 
you have the dimensions. 

Mr. Porter: I think it is our function to recommend what will 
give the best results although they are not in practice right now. 

Mr. Ziebarth: Answering Mr. Crabtree's question, the Bell and 
Howell camera aperture is 0.720" high x 0.965" wide, and their 
printer will print the full picture size, 0.750" high x 1.000" wide. The 
film, being transparent outside of the camera aperture, would leave 
a black frame around the picture when printed. We have been using 
these sizes for several years. 


Transactions of S.M.P.E., March 1926 

Mr. Palmer: I am heartily in favor of the recommendation as 
given because it has been very ably and fully demonstrated before 
this Society that the black border does give a steadier picture, and I 
think that a square cornered picture is better looking on the screen 
than the round cornered one. 

{Motion passed to adopt above dimensions.) 

Fig. 3. — Proposed dimensions for fihn splices. 

Projector Speeds 

With regard to projector speeds, we again recommend as stand- 
ard practice 80' per minute, with a maximum of 85' and a minimum 
of 75'. 

{Motion passed to accept above recommendation.) 

External Diameter of Projection Lens Barrels 

Regarding the external diameter of projection lens barrels, we 
recommend 2-1/32" for No. 1 lenses and 2-25/32" for No. 2 lenses. 
{Motion passed to accept these dimensions.) 

Report of Standards and Xoniendature Committee 13 

Camera Cranking Speed 

Regarding camera speed, we recommend as recommended prac- 
tice: — a camera taking speed of 60' per minute, with a minimum of 
55' and a maximum of 65' when normal action is desired, in connec- 
tion with the Society of Motion Picture Engineers recommended 
practice of 80' per minute projection speed. 

(Motion passed to accept speeds recommended as above.) 

Film Splicing 

Regarding film splicing, we propose as recommended practice 
the dimensions shown in Fig. 3. 


Mr. Porter: Since the report was prepared, we have had Mr. 
Denison's discussion, in which he told us that the Technicolor people 
use a narrower splice, and that Famous-Players use a full hole splice. 

Mr. Ziebarth: The splice shown in Fig. 3 is the same as the 
Famous Players except that the}^ have moved the splice so that the 
scrape leaves the dividing line between the pictures. This does not 
make the splice any stronger, and there is the possibility of it show- 
ing on the screen when projected. 

Mr. Denison: The reason we moved the margin over was to 
take care of checking; it doesn't make the splice better. 

Mr. Richardson: I understand that this is not a recommenda- 
tion to others than manufacturers although it may be followed by 
men in the projection room. 

Mr. Porter: We are proposing this as "recommended practice." 

Mr. Griffin: Regardless of recommended practice, I think Mr. 
Denison's point is well taken. I think there is still room for con- 
sideration of this splice matter, and there is no doubt that Mr. 
Denison's splice does protect film after it has become slightly dam- 

Mr. Ziebarth: I do not believe that moving the sphce 0.015" 
will stop the checking or strengthen the film after it is checked. 

{Motion duly passed to refer the matter hack to the Committee) 

Tolerances in Film Dimensions 

Your Committee again lays before you the question of tolerances 
in the dimensions for 35 mm film. 

14 Transactions of S.M.P.E., March 1926 

Considerable data on the question of film shrinkage were ob- 
tained by the Bureau of Standards at Washington, D. C, and the 
tests they made are summarized as follows : 






Requested by 
The U. S. Patent Office in letter dated January 16, 1925. 
1 . This work was done to answer the following questions : 
First: What amount of shrinkage will occur if a strip of 
standard positive motion picture film having sensitive 
coating on one side be soaked in water for ten minutes 
and then dried? 
Second: So soaked for /or^2/ minutes and then dried? 
Third: Will either of the films so treated further shrink when 
exposed to form a positive image, developed, washed, 
hut not fixed, and dried? 
Fourth: Does a film which has been treated as in Questions 1 
or 2 shrink to a greater or less extent than an untreated 
film when further treated as in Question 3? 
In the next experiment, the films Nos. 1, 2, 3, 4, 5, 6, 10, 11, and 
12 were exposed or printed to form a positive image, developed for 
five minutes in a standard positive motion picture developer (E.K.Co. 
Formula No. 16) washed for thirty minutes and dried without fixing. 
The interval of time between the drying and measuring was 22 hours. 
Tabulating all the results obtained : 

Dimensional Changes in Length in mm. per Meter of Length 

Dried but 


not devel- 

washed and 




No washing 




10 m. washing 




20 m. washing 


40 m. washing 




Following the above experiments, films Nos. 1, 2, 3, 4, 5, 6, 10, 
11, and 12 were fixed in hypo, washed thoroughly, and dried, showing 
the f pllowing additional shrinkage ; 

Report of Standards and Nomenclature Committee 15 

Millimeters per Meter of Length 
12 3 4 5 6 10 11 12 

0.496 0.190 0.406 0.272 0.268 0.346 0.382 0.470 0.274 

Films 3, 10, and 12 were later soaked in water for two hours, and 
their lengths measured wet. The gains in lengths were as follows: 

Millimeters per Meter of Length 
3 10 12 

5.684 7.550 5.304 

Average 6.174 

(Signed) George K. Burgess, Director. 

The Paris Congress seems to consider it desirable to take shrink- 
age into consideration and specify tolerances on the film dimensions. 
The action taken by the Congress was as follows: 

New Positive Film 

The dimensions below are fixed on the hypothesis of a shrinkage 
not exceeding 1.5 per cent , after which the film has been subjected 
during 720 hours to a current of moving air at a velocity of 3 m per 
second at a temperature of 60° Centigrade and a relative humidity 
of 70 per cent. 

Pitch : The hundredfold of pitch, measured between homologous 
points of two perforations separated by 100 complete perforations, 
should be equal 

+ 1.00 mm. 

to 475 

-0.00 mm. 

+ 0.05 mm 
Distance from axis to axis of two rows of perforations 28.15 

-0.10 mm. 

New Negative Film 

Pitch: The hundredfold of pitch, measured as above, ought to be 

+ 2.00 mm. 

equal to 475 

-0.00 mm. 

All other dimensions and forms of perforations as for the positive film. 

-r .£ -c £ 

Kodak Positive 

1.37790" +0.0 


35mm +0.0 

28. 15mm 

1.98 mm 





. E 

b £ 

00 00 
'^ OS 

• 00 

o ^ 


Kodak Negative 

Bell b- Howell 

1.3779" +0.0 


35mm +0.0 

28. 15mm 

1 .85 mm 


0. 1870" 

b £ 

00 00 
rf OS 


304 mm 

German Negative 

and Positive 

Raw Stock 

34.9mm +0.1 

1. 110" 

+ 0.01 
28.2mm -O.Ol 

o o 
b b 
+ 1 




o o 
b b 
+ 1 




o o 
b b 
+ 1 




304mm +0.160 





1 1 

1 1 
b, 1 


+ 0.050 
28. 15mm -0.050 





+ 0.013 
4.73mm —0.0 

§■« ! 
^^ 1 

28. 15mm 

1 .85mm 


4. 76mm 

British Newly 
Finished Prints 

1.375" +0.003 

35mm +0.0 





:n .£ 

00 fC 

o ^• 


; E 

O 00 

vO ^ 

•* Ov 

■ 00 

o ^ 

11.9375" +0.0 


303.21mm +0.0 




British Finished 

Negative, Positive 

Raw Slock 

1.375" +0.003 

35mm +0.0 


1. 110" 



0. 1870" 

b £ 

00 00 

-* OS 

• 00 

O -H 

11.9687" +0.0 


304mm +0.0 





.\< 1 

= 1 

o 1 

Q 1 

w 1 

f^ 1 



i so 

M "3 

3 C. 

u E 

2 <r. 

Report of Standards and Nomenclature Committee 


Your Committee feels that it is impractical to set tolerances to 
allow for shrinkage which various manufacturers think their film will 
undergo. We beUeve we were absolutely right when we set dimensions 
for freshly perforated negative raw stock, and we do not recommend 
the addition of any tolerances or an effort to consider positive film 
when it is ready for projection. 

{Motion made and seconded not to recommend tolerances.) 

















Fig. 4. — Indicating dimensions referred to in above table. 

Cainera Reel Cores 

We have found so little interest among the camera manufacturers 
in the question of standardizing film reel cores that we recommend 
laying this matter on the table for the time being. 

The Paris Congress ruled as follows on this question : 

Film Reel Cores for Magazines of Taking Cameras 

While reserving for the next Congress a definite decision, after 
careful investigation the Congress invites manufacturers to conform 
for the creation of new models to the dimensions recommended below : 

Exterior diameter 50 mm. 

Interior diameter 20 mm. 

Width (equal to that fixed for the film) 35.0 "^^'^ ^^' 

— 0.1 mm. 


Transactions of S.M.P.E., March 1926 

Fig. 5. — Recommended dimensions for camera bobbins and raw film core. 


Mr. Palmer: What is the diameter the Eastman Company is 

Mr. John Jones: It is practically one inch or 25 mm. 

I ask that it be referred back to the Standards Committee. The 
information came in late, and we have had the matter up before for 
consideration and would like more time on it. I make that as a motion. 

{Motion passed to refer the matter hack to the Committee.) 


Your Committee must confess that it has fallen down completely 
on the question of standardizing sprocket design. No American data 
have been collected on this subject since the Schenectady meeting. 

The Paris Congress had considerable to say on this subject, as 

Sprocket Teeth 

For projectors, apparatus for taking, perforators, pull-down; 
Dimensions of 16 tooth sprockets: 

Width of sprocket 34.80mm. ±0.2 

Distance from axis to axis of teeth 

(across pitch) • 28.00mm. ±g:o4 

Width of aperture 24.00mm. 

Width of lateral bearing surface 5.40mm. ±0.1 

Diameter of sprocket at the base of the 

teeth .23.85mm. ±0.05 

Total diameter of sprocket including 

teeth .26.45mm. ±0.05 

. ^ Angular separation of teeth 23° 30min. 

Report of Standards and Xoinendature Committee 


The base of the teeth (cut C D) is included between two hmits 
respective!}' defined by a rectangle (of which the apex can be option- 
ally rounded) : 

width 1.7mm. thickness 1.40mm. l^^os 

and through the figure formed by the two long sides of the same rec- 
angle and by the arcs of the circle circumscribed to the rectangle (b) 
(the apex can be optionally rounded) 

Width of teeth at the head 1.5 mm. 

J 1. 

I -^ 

Trif/mr'rr I ' 

A B 





I [e sectiom vz 

^/A . 1e section yz 



-Indicating dimensions referred to in following table. 

The cross section of teeth through a plane perpendicular to the 
axis of the sprocket allows two arcs of symmetrical circle of 1.8 mm 
radius normal to the circumference representing the section of the 

< -^ 


23.85mm -0.05 

IT) 1/-. 

o o 
o o 

+ 1 



o o 
o o 

+ 1 




1 .7mm for rectangular 

2. 1mm for circular 

o o 

o o 

+ 1 


1 . 5mm for rectangular 
15° for circular shape 





26. 54mm 




15°-20° angle 

5 = 




+ 0.0 
23.81mm -0.002 


+ 0.0 
26.41mm -0.002 


1 .70mm 





26. 75mm 








5; ■« 1 o o o o 

o o o o 

v-i ^ in iJi 

O O (M CM 

o o o o 






_c ■ 


British Propo 
New Standa 

0.942" +0 

23.927mm -0 


1.045" -0 


26.540mm -0 

1.10" -0 

27.90mm -0 

British Old Standard 

0.9375" +0.003 
23.812mm -0.0 


1.1025" -0.001 


28.0mm -0.025 

0.075" +0.001 

1.90mm +0.025 

1 u 











O O 

d o 
+ 1 




. E 

^n E 

in <*5 

ir> -H 

00 r~ 

; £ 

; £ 
— o 

00 o 

; E 


00 vO 

^ E 
S <-^ 

00 r~- 
— •* 

: E 
•<* t^ 

00 « 


; E 
re t^ 

ID o 

00 t^ 


00 o 

00 r- 

; E 

00 ^o 


; £ 
<~^ 1^ 

•O O 

00 t- 


^ E 





£ -^ 

£ E 
E E 

1- <" 
o -^ 
1- o 

- -f t;; > 2 

E £ 
£ E 



































































— ' 











































ck; a^ 






Transactions of S.M.P.E., March 1926 

Number of teeth in taking: One shall take account in the con- 
struction of the apparatus that the number of the teeth in contact 
with the film shall never exceed six. 

Sprockets with more than sixteen teeth : Sprockets having a 
number of teeth above 16 should be established on dimensions equiv- 
alent to those defined above; the number of teeth in contact with 
the film should not exceed six. 

Distinctive marks: The mechanical parts conforming to the 
dimensions above provided shall carry a distinctive sign constituted 
by the letter S (initial of Standard) at the center of a circle and the 
name of the manufacturer. 


Mr. John Jones: We have not had time to analyze these dimen- 
sions for sprockets, and I would like it referred back to the committee. 

Mr. Crabtree: Are these dimensions intended to cover cameras, 
printers, processing machines, and projectors? 

Mr. John Jones: Every case should be analyzed. The design of 
the sprocket should be made to conform to the number of teeth 

{Motion passed to refer the matter hack to the Co?nmittee.) 

Film Gate 

The Paris Congress recommended on Projector Gate width as 
follows : 

Width of gate runners on all apparatus, projectors, machines, etc. 

Qc 1 +0.10inm. 
OO.l -O.OOmm. 


_ nr»nr»_ 


Fig. 7.— Recommended dimensions of projector gate runners. 

Report of Standards and No7nendature Committee 23 


We again present to you the definition of "Scene" as amended 
at Schenectady, i.e., "A division of the story showing continuous 
action in the same locale or set, and usually taken from the same 
point of view." 

{Motion passed to accept definition as above.) 

Reflector Arc Lamp 

We have not been able to improve on the definition for "Reflector 
Arc Lamp," which was referred back to us last May. W^e, therefore, 
present it again as follows: "In a motion picture projector, an arc 
light source in combination with a reflector, to project the light beam 
through the aperture." 

(Motion passed to accept definition as above.) 


In conclusion, the Chairman thanks the members of the Com 
mittee for the hearty support they have given him during the past 
two years, and also expresses his appreciation of the confidence placed 
in him by the President in appointing him to handle such important 
work for the Society. 

(Signed) L. C. Porter, Chairmaii 
J. G. Jones 
Herman Kellner 
F. F. Renwick 
F. H. Richardson 
October, 1925. 

DISCUSSION (continued) 

Dr. Sheppard: I do not wish to delay the meeting, but you may 
be interested in hearing something about the International Congress 
of Photography in its relation to cinematography. So far as this 
Society is concerned, it was represented by only "unofficial observers" 
but its specific recomendations on standards were duly brought before 
the meetings. 

The Sixth Congress was notable for more than one reason. It 
was the first international photographic congress held since the Euro- 
pean War, and occurred after an interval of fifteen years. The prog- 
ress of photography has been very great in this time, while cinematog- 
raphy has come to the front ranks as a major industry. Indeed, in 

24 Transactions of S.M.P.E., March 1926 

view of this advance as well as by reason of the logic of operations, it 
is perhaps to be expected that photography will before long be recog- 
nized as a section or dependent phase of cinematop-raphy. It was in 
any case natural that one out of four sections of the Congress' pro- 
ceedings was devoted to cinematographic standardization. Two other 
events marking the occasion may be mentioned. It coincided with 
the French celebration of the hundredth anniversary of the invention 
of photography by Niepce (actually of date 1822), and the inter- 
national circle was happily completed by a representative German 
delegation. Those who attended will always doubt that the "con- 
fusion of tongues" referred to in connection with the building of the 
first skyscraper is a sign of disunion and division. The necessity of 
translation may slow down the proceedings, but the effort to under- 
stand and to make understood seems to ensure a thorough discussion 
of the points at issue. 

A word on the constitution and prospects of the Congress may 
not be amiss. It is to be remarked that there exists a sort of "board 
of regents" for this International Congress in the shape of a Perma- 
nent Commission largely controlled by theSocieteFrangaise dePhoto- 
graphie, the Association Beige de Photographie, the Fotografiska 
Foreningen of Scandinavia, and the Royal Photographic Society of 
Great Britain. The United States and Germany have no representa- 
tive national photographic societies like these to ensure their partici- 
pation and forward their interests in regard to the International 
Congress, but for this country the Society of Motion Picture Engin- 
eers and the Optical Society of America are in touch with the situation 
The next Congress it is proposed to hold in London in three years' 
time. A movement westward having thus begun, it is eminently 
desirable that the following Congress be held in America, and I 
venture to hope that the Society will bear this in mind. The meetings 
were held in the rooms of the Societe Frangaise de Photographie, so 
that a genuine photographic environment and proper facilities for 
sectional meetings, specific demonstrations, and so forth were secured. 
Registration commenced on the morning of June 29, and those attend- 
ing the Congress were provided with a very full set of abstracts of the 
communications to be made. These were available both in French 
and in English through the courtesy of "Science et Industries Photo- 
graphiques" and "The British Journal of Photography," respectively. 

After the opening session, presided over by Professor Ch. Fabry 
of the University of Paris, the Congress proceeded to the business of 

Report of Standards and Nomenclature Committee 25 

sectional meetings. The four sections and the vice presidents ap- 
pointed to secure international representation were: 

Section I. (Theory of Photography and Sensitometry) 

Mr. Callier, Director of the Belgian Optical Company, Ghent 
(Belgium) ; Dr. R. Garriga-Roca, Director of the Barcelona Photo- 
graphic Paper Company (Spain) ; Professor H. Luther, Director of 
the Photochemical and Photographic Institute, Dresden (Germany) ; 
Dr. S. E. Sheppard, Assistant Director of Research, Eastman Kodak 
Company (U.S.A.); Dr. T. Slater-Price, Director of the Laboratory, 
British Photographic Research Association (Great Britain) . 

Section II. (Technical and Artistic Photography) 

Mr. G. Cortezo, Secretary of the Royal Photographic Society of 
Madrid (Spain); Professor R. Koegel, Munich (Germany); C. de 
Santeul, (France). 

Section III. (History) 

Professor J. Albertotti, Padua University (Italy) ; L. Cartagena, 
Secretary of the Spanish Photographic Society (Spain) . 

Section IV. (Cinematography) 

C. I. Brichta, Curator of the Cinematographic Division of the 
Technical Museum, Prague (Czecho-Slovakia) ; L. Gaumont, Honor- 
ary Chairman of the French Cinematographic Syndicate (France); 
Professor E. Lehmann, Charlottenburg (Germany); A. S. Newman, 
delegate of the English Kinematography Manufacturers Association 
(Great Britain). 

Before the conclusion of the opening session, Mr. L. P. Clerc 
thanked the members of the Permanent Commission for securing 
participation by their nationals and the various donors, notably the 
Eastman Kodak Company, whose financial support enabled the 
printing of the Congress Transactions to be effected. 

The meetings of Section IV. (Cinematography) were always 
fully attended, and the standardization proposals debated in great 
detail and at length. The standardization of sprocket dimensions did 
not appear to offer great difficulty in the matter of obtaining agree- 
ment. Points agreed upon as guiding principles were (a) that the 
sprocket dimensions should be the same for cameras, perforating and 
printing machines, measuring machines, and projectors; (b) that 
sprocket dimensions must allow for the expansion and shrinkage of 
the film. A maximum shrinkage of 2 per cent was assumed; (c) if not 
more than six teeth engaged, danger from moderate shrinkage would 
be avoided. 

26 ■ Transactions of S.M.P.E., March 1926 

On the other hand, the question of standardization of film dimen- 
sions proved a very ticklish matter and eventually one on which 
complete unanimity was not attained. The proposal of the French 
(M. Lobel) to standardize shrunken film was found not to be feasible 
in view of the variations in the material. It was considered that 
standardization should be limited to: 

(a) raw film dimensions leaving the perforating machine, 

(b) raw film dimensions with a contingency of maximum shrink- 

In regard to perforations, both the Eastman Kodak positive 
perforation and the Pathe positive perforation (new type with 
rounded corners) were accepted as standard. This option departs 
from the principle of rigorous standardization, but it was pointed out 
that the over-all dimensions are the same in both, so that both can be 
run on any machine. Whilst a generally satisfactory compromise was 
felt to be reached on positive film dimensions,this could not be effected 
for negative film. The European and British delegates strongly 
favored substantial identity of dimensional standards for both posi- 
tive and negative film; the American viewpoint that the existence 
of different negative film perforations and standard dimensions cor- 
responding to the existing Bell and Howell cameras should be recog- 
nized was urged by the Eastman Kodak Company's representa- 
tives but without affecting the general sense of the meeting in 
favor of substantially identical dimensions for both negative and 
positive, which was so affirmed by vote. 

On the motion of Mr. Vinten, seconded by the writer, it was agreed 
that the recommendations reached should be held in abeyance for six 
months to allow for criticism, ratification, or objection,by the national 
representative bodies of the different countries. A committee to act 
as "clearing house" for these reactions was formed consisting of five 
members: Professor E. Lehmann (Germany), L. Lobel (France), W. 
Vinten (Great Britain), Brichta (Czecho-Slovakia) ,and a member of 
the Society of Motion Picture Engineers, to be appointed (U.S.A.). 
This permanent committee is to collect and report on all material 
furnished from different countries affecting the standards recom- 

Another aspect of the activities of the Congress which does not 
come under the cinematographic section is, however, of great im- 
portance for cinematography. This is the standardization of sensi- 
tometric conditions. In the discussion of these questions by the 

Report of Standards and No7nendature Committee 27 

section it was noteworthy that the principal point of difference, 
namely, the standard of light, was largely affected by motion picture 
practice. The theoretical unit of light for photographic purposes is 
recognized to be one candle power of white light given by a black body 
at 5000° K. This apparently purely theoretical and academic defini- 
tion is based on the assumption of daylight or sunlight as a normal 
condition of photographic exposure. It is, however, difficult to realize 
a practical standard of white light of 5000° K., and the recommenda- 
tions of the section were in favor of the practical unit of 2360° K. 
A point in the discussion was that the increasing practice of artificial 
illumination in motion picture negative making on the one hand and 
the universal use of artificial light for the making of positives throw 
considerable doubt on the fundamental reason for taking a daylight 
or sunlight unit. On the other hand, a standard of light of 2360° K. 
is a low temperature value compared with the sources used in motion 
picture work. It is evident that the sensitometric standardization 
continues to be dominated by consideration of past "still" photog- 
raphy and that the subject requires very definite consideration from 
the view point of cinematography. 

There is sometimes a disposition to regard the proceedings of 
such congresses as praiseworthy but unimportant. This is likely to 
become less and less true. No country can afford, in regard to its 
industrial interests, to neglect the technological trend of its compeers. 
The sense, if not always the authority, of this trend tends to be ex- 
pressed in international standards. In this sense the conclusions 
reached by the cinematographic section of the Sixth Congress are 
significant and important. 

President Jones: I am sure that the Society appreciates the 
work which Mr. Porter and his committee have done in preparing 
this and previous reports dealing with nomenclature and standards. 
I feel that we as an organization owe them a great deal, and in behalf 
of the Society I tender our thanks and appreciation for the good work 
that they have done. I know it has involved a great deal of work on 
his part in order to place these matters so clearly and concisely before 

I take this opportunity to suggest, in view of the fact that we 
have adopted certain standards not entirely in accord with the recom- 
mendations of the Paris Congress, that the Congress be informed as to 
our actions and that the differences existing between our standards 
and their recommendations be definitely pointed out. They should 

28 Transactions of S.M.P.E., March 1926 

also be informed as to the reason for our adopting the standards we 
have. The recommendations of the Congress were made with the 
understanding that they were to stand six months before final ap- 
proval, thus giving an opportunity for those disagreeing to register 
protest and to present their viewpoint on the matter. It is desirable 
that the Congress should have a definite statement of our actions 
and the reasons therefor. It seems to me desirable to prevent the 
final adopting by the Congress of standards not in agreement with 
our own. I do not know exactly how this matter should be handled, 
but I suggest that the chairman of the Standard's Committee, or per- 
haps our president, should forward to the office of the Congress in 
Paris a complete statement of the situation. This matter should be 
attended to promptly, since the time remaining before the expiration 
of the six months' probationary period is rather short. 


Report of Proceedings of International Congress of 
Photography held at Paris, 1925 

L. P. Clerc 

First Meeting, June 29, 1925 

DR. A. S. Newman representing the Royal Photographic Society 
of Great Britain and the Kinematograph Manufacturers Asso- 
ciation of England read the following address: 

It is evident to all those who are engaged in whatever capacity in the Cine- 
matograph industry, that the unification of its products and certain essential 
parts of apparatus is a vital necessity. 

Economical production, absolute interchangeability, and perfect quality 
can only be maintained under very favorable conditions. The first and most 
important of these conditions is the standardization of essential dimensions. 

It is surprising that an industry of such importance can have existed for so 
long and have made such progress without international standardization. Cine- 
matography interests all people, appeals to an army of scientists, engineers, and 
organizers. It employs large staffs; its products are found in all countries. 

Some years ago we recognized in England the necessity for standardization 
in the cinematograph industry, and we think the Kinematograph Manufacturers 
Association was the first to institute a committee to that effect. Mr. W. C. Vinten 
and myself sat on this committee from its formation. Mr. Vinten is actually its 
president. Mr. Vinten and myself are also members of the Royal Photographic 
Society, and when this Society recently appointed a committee to deal with the 
same question, we were appointed members of this committee. We thus represent 
both societies. 

We also have with us Mr. Blake of the Kodak Company; Major C. J. P'ox, 
treasurer of the Kinematograph Manufacturers Association; and Mr. A. W. King- 
ston, delegate of the Camera Men's Society; all three members of the Royal 
Photographic Society. 

I will first describe to you what the standards committee of the Kinemato- 
graph Manufacturers Association has done up to the present time. At the time 
of our first meeting in the early part of the year 1920 complete chaos existed as 
regards dimensions of film issuing from various factories. No one knew exactly 
what should be the pitch of perforation, the width of film was not fixed, the shape 
and dimensions of perforations varied from one manufacturer to another, also 
their position in relation to the edge of the film. Each manufacturer employed, 
particularly for sprockets, the dimensions suggested to him b}^ his personal ex- 


30 Transactions of S.M.P.E., March 1926 

perience acquired by the most onerous methods, losses of time and money, com- 
plaints of customers, etc. 

I think I can claim for our committee that it had a useful influence on the 
cinematograph industry throughout the world. Notwithstanding the fact that 
the dimensions proposed by us have not been universally adopted, the discrepan- 
cies have already been lessened. We have, however, encountered much opposition 
on the part of certain branches of our industry and a certain dislike of all altera- 
tions, even trivial details. 

We have been pioneers and have encountered opposition — which is the lot 
of all pioneers. We do not complain for we find a tendency becoming more notice- 
able towards unification in the sense that we have suggested. 

Our first care was to recommend adoption of measurements very little dif- 
ferent from the average of those most generally employed, seeking to follow the 
line of least resistance and to reduce to a minimum the inconveniences of any 
alterations on the manufacturing side. The majority of films vary only slightly 
from the dimensions we have suggested, and having fixed the limits of tolerance 
we can state that practically all films new or old which have passed through our 
hands have complied with these limits. It is only quite exceptionally that we 
have encountered new films diverging from the dimensions we have recommended. 

Our committee had been in existence for a year when the Society of Motion 
Picture Engineers of America appointed in its turn a standards committee, with 
which we soon entered into relations. About the same time we sought to discover 
if similar committees were in existence in other countries, but found it impossible 
to obtain information on this subject. Eighteen months after its formation our 
committee published a report, copies of which were distributed throughout the 
world. It was received with numerous criticisms. If certain of these were in the 
nature of complaints others were justified, and we had to take account of them. 

Our colleague Mr. Vinten took part in a Congress in the United States as a 
delegate from our committee. The American committee accepted a certain 
number of our conclusions and from that time an effective collaboration between 
the two committees was assured. 

We much regret that at the last moment the two delegates from the Society 
of Motion Picture Engineers found themselves unable by personal circumstances 
to attend this Congress, but we hope that, thanks to the presence amongst us of 
several members of this Society, an international agreement can be concluded. 
The attendance of the United States is the more necessary to us, as this country 
probably controls at least half of the world's production of cinematograph films, 
and consequently nothing truly international can be realized without its agree- 
ment. Let us hope at least that our decisions will be such as may commend them- 
selves to our American confreres. 

The proposal made to consider as fundamental measurements the dimensions 
of the Maltese Cross sprocket, and to deduce from them the normal dimensions of 
films, has our entire approbation. Possibly, some will ask why our committee has 
not adopted the same starting point. At the beginning of our labors the variations 
in the dimensions of films were much greater than at present. These dimensions 
had been progressively evolved from those adopted bj^ Edison for the Kinetoscope. 
Measures taken after nearly thirty years on old films which have shrunk to a 
■greater or less extent had, for example, reduced the pitch by about 2.4 mm. Our 

Internotional Congress of Photography — Clerc 31 

committee thus started from the middle of almost inextricable difficulties to 
establish a basis from which standard sprocket dimensions could be computed. 

In the letter addressed to our Society your secretary Mr. Lobel asked that 
our delegates should be given full powers to permit the rapid settlement of points 
under discussion. In our opinion the time that the Congress can devote to the 
discussion of these questions is too short to permit a definite settlement of matters 
of such importance. For thirty years most complete disorder has reigned, and we 
think that a year would not be too much to arrive faithfully at the most favorable 
decision for the interest of our industry. We consider the method adopted by our 
American colleagues much wiser; when their committee decides on the subject of 
new dimensions, the application of this decision is advertised for six months. If 
no serious objection is raised against this decision, it is put into force at the end of 
this period In the event of any opposition arising, the matter is further discussed 
and the application is again advertised for six months. 

But consider, Gentlemen, we have come here with the hope and firm in- 
tention of making final decisions in the interest of all concerned and if I raise this 
objection on behalf of the Society which I represent it is in no way in a spirit of 
obstruction. I trust that you will receive these remarks in the same spirit with 
which we make them. We have come here in our own interest, certainly, but also 
in the interest of all. We are now at a scientific meeting and science knows no 
reticence or politics. 

Our powers permit us, except as regards those dimensions in which we have 
already come to an agreement with the Society of Motion Picture Engineers, to 
listen to all reasonable proposals and to collaborate in your decision, but to avoid 
any misunderstanding we must declare that if the fact of sitting on the Congress 
involves for us the obligation to accept in any of the cases the decisions of the 
majority, we cannot think it right to partake in these discussions. If such were 
the case, we would ask you none the less to authorize us to attend your meetings 
but to abstain from committing ourselves or voting. 

I trust. Gentlemen, that this declaration to which you have accorded your 
kind attention will have clearly defined the attitude of the English delegates. As 
for us, we are absolutely assured that we can count upon the kindness and 
cordiality of all our colleagues. 

In accordance with Mr. Newman's proposal the Congress agreed 
not to consider decisions final for a period of six months, during which 
period various international organizations might raise any objections. 

Mr. W. C. Vinten on behalf of the Kinematograph Manufac- 
turers Association and Mr. M. Flinker, president of the Standards 
Committee of the German Technical Kinematograph Society, on 
behalf of this Society distributed notes and sketches showing pre- 
cisely the dimensions actually standardized by each of these inter- 
national groupings. 

On the proposal of Mr. Lobel, president of the Cinematograph 
section of the French Photographic Society, and after interventions 
from Messrs, Newman and H. Joachim (Akt, Ges. Hahn), the Con- 

32 Transactions of S.M.P.E., March 1926 

gress decided to discuss in the first place sizes of Maltese cross sprockets 
for projectors. Mr. M. Flinker considered differences between sizes 
adopted by the German Technical Kinematograph Society and the 
proposed sizes negligible, and therefore, accepted the latter. 

Mr. L. Lobel translated an article published by Mr. Flinker in 
No. 12 of ''Die Kinotechnik" (25th June 1925), reprints of part of 
which had just been distributed. 

In this article "On the present state of Cinematograph Standard- 
ization," Mr. Flinker recalled that in few cases were goods so much 
the object of international exchange as cinematograph films. The 
manufacture of machinery being centered in a small number of 
countries, one would naturally expect that before long mutual adapta- 
tion of films and apparatus would be effected. If none of the sugges- 
tions for standardization which the author enumerated had been put 
into effect, it was because with the exception of the system proposed 
by the D.K.G. (German Technical Kinematograph Society) none of 
them constituted a complete list. A table adjoining the article com- 
pared the various international standards and pointed out the dif- 
ferences. He approved of the step taken by the Cinematograph 
Section of the French Photographic Society and declared that the 
German delegation came to the Congress with the intention of work- 
ing for the common interest. 

Mr. Newman mentioned that if the standards committee of the 
K.M.A. had not specified the shape of teeth, it w^as because this 
question was about to be discussed when the invitations to the present 
Congress were sent out, and it appeared wiser to leave it to the 
decision of the Congress. 

Professor E. Goldberg (lea Akt. Ges.) and Dr. Joachim drew 
attention to the necessity of fixing the number of teeth on the sprocket 
engaging with the film for a definite number of teeth, the tolerances 
of shrinkage or stretching being a function of this number. He pro- 
posed the engagement of seven teeth. Mr. J.Marrette (Pathe Cinema) 
considered that the pitch should be independent of the diameter of 
the sprocket and that one should fix either the length of the arc on 
which the film should engage with the sprocket or the number of 
teeth on the sprocket engaging with perforations of the film. The 
pitch of sprockets should be measured at the base of the teeth. 

Mr. Flinker mentioned that the standards committee of the 
D.K.G. took into consideration the number of teeth engaged in the 
film. He recalled an article published by him in 1921 (Kinotechnik, 

International Congress of Photography — Clerc 33 

V.III. No. 18, p. 685) in which he showed that for a' shrinkage of 2 
percent there was no danger to the film until the number of teeth 
engaging was increased to eight. It is up to the manufacturer to 
conform with this. The following proposal of Mr. Marrette was 
accepted by the Congress. 

A 16 tooth sprocket shall engage with the film with a maximum 
of six teeth. 

As regards the diameter of the sprocket measured at the base 
of the tooth, Mr. M. Flinker proposed the diameter already adopted 
by the D.K.G. of 23.81 mm with a negative tolerance of 0.02 and 
without a positive tolerance. Mr. Marrette was quite agreeable to 
23.81 mm ±0.01. Messrs. Vinten and Newsman indicated that it was 
owing to the fact that the English climate was very damp (film thus 
showing less shrinkage) that the K.M.A. had just been led to recom- 
mend a slight increase on the diameter of sprockets and to adopt for 
the diameter at the base of teeth dimensions of 23.927 to 23.977 
admittive for the pitch of positive film a normal value such that the 
length measured over 64 perforations would equal 303.21 mm plus 
0.0 and minus 0.79. 

Dr. H. Tappin (Goerz Photochemische Werke) stated that the 
shrinkage of films made at the same works at different times is never 
constant and that it is impossible for manufacturers to give precise 
values for the pitch of the film when ready for projection. Professor 
Goldberg recalled that under the conditions specified in the proposals 
of the German committee the Agfa, Goerz, and Lignose factories were 
engaged in keeping the shrinkage to a maximum of 2 per cent. 

Mr. L. P. Clerc read the following observation communicated by 
Dr. C. E. K. Mees, (Eastman Kodak Compam^) : 

The standardization of fihn dimensions and their perforations is for us of very 
great importance. In discussing this question with the Societj^ of Motion Picture 
Engineers, Mr. L. Lobel, president of the Cinematograph Section of the French 
Photographic Society proposed that the standards for perforated film should . be 
based on the films having already passed through various manipulations and 
drying, the manufacturer in perforating the film having regard to the percentage 
of shrinkage which he thinks probable for the products of his factory. This pro- 
cedure appears to us absolutely impracticable and would be the cause of endless 
trouble. In the establishment of standards one can only standardize the mechan- 
ical parts; thus a perforator works on raw stock and not on positive film ready for 
projection. If each manufacturer were at libertj^ to adopt for the perforation of 
this raw stock as many different pitches as he may be led to suppose his films 
have shrinkage values we should find ourselves in a state of complete chaos. 

34 Transactions of S.M.P.E., March 1926 

Apparent!}^ the French Photographic Society considers fihn shrinkage a 
simple and well defined phenomenon and deems that a film of known origin will 
always show the same shrinkage. Unfortunately we know definitely that this is 
not the case, and we must protest strongly against the adoption of any recom- 
mendation which would lead to the modification for each manufacturer of the 
pitch of his perforator. 

The following proposal formulated by Mr. M. Flinker on behalf 
of the German delegation was adopted unanimously, applying im- 
mediately to the German and French machinery manufacturers but 
with reservation for a period of six months by the English delegates 
and American members. The diameter of the sprocket measured at 
the base of the teeth is fixed at 23.85 mm +0.05. 

Second Meeting, June 30, 1925 

Mr. Newman in the chair. On the question of a decision on the 
width of the Maltese cross sprocket, Mr. Decaux (Establissement 
Gaumont) remarked that it was preferable that this measurement 
should be less than the width fixed for the film, that is to say, less 
than 35 mm. In practice when a Maltese cross has been in use for 
some time, the films being always narrower than 35 mm particularly 
when they are old, there is produced a certain wear on the diameter 
of the sprocket which reduces its diameter except at its two extremi- 
ties which maintain their original diameter. If the film of normal 

35 mm width be now run on this machine, it will bear on the raised 
sides of the sprocket with a risk of damage. It is thus preferable that 
the length of the sprocket should be reduced. Mr. Decaux proposed 
the size of 34.8 + 0.2 mm, which will give manufacturers the required 
latitude to avoid this trouble. The Congress adopted this proposal 
unanimously : 

The width of the sprocket (length over cheeks measured parallel 
to the axis) is standardized at 34.8 + 0.2 mm. 

The proposal of the French Committee conforming to the dim- 
ensions adopted by the D.K.G. for a distance between teeth measured 
from centre to centre of the tooth was adopted : 

The distance from centre to centre of the two rows of teeth is 
fixed at 28 mm+0.0-0.4. 

After an intervention by Professor Goldberg saying that the 
tolerance shown for the exterior diameter of the sprocket should be 
slightly increased, the Congress decided that: 

The overall diameter of sprockets including teeth is fixed at 
26.45 + 0.5 mm. 

International Congress of Photography — CJerc 35 

The following proposal was also adopted without discussion: 

The width between cheeks is fixed at 24 mm. 

From the above figures it will be seen that the width of each of 
the two cheeks will be 5.40 mm. 

As regards the shape of teeth. Mr. Newman proposed that the 
driving faces of the teeth should be contained within a curve gener- 
ated from the circle, the maximum allowance being made towards the 
top of the tooth. It will be sufficient, for example, to describe a circle 
very slightly less than the actual diameter of the sprocket. ]Mr. 
Flinker asked that the tangents at the base of each tooth should be 
produced below the corresponding diamete>r. ]\Ir. Decaux observed 
that in cutting the sprocket teeth there was always a slight radius at 
the base due to the sharp corner of the milling cutter being slightly 
removed. The film cannot thus adapt itself to a portion of the base 
of the tooth normal to the working diameter. For the last twenty 
3^ears the Gaumont Company have avoided this trouble by leaving 
at the base of the tooth a slight undercut sufficiently deep for the 
working base of the tooth to retain its correct form, notwithstanding 
SLTiy alterations in the shape of the cut. No decision was made on this 

On the question of the shape and dimensions of the section of 
the base of the tooth, Mr. Vinten proposed to adopt as a section of 
the tooth the portion of a circle of 2.16 mm diameter contained be- 
tween two chords symmetrical about the diameter and 1.27 mm apart. 
Mr. Flinker considered that it was useless to radius the lateral faces 
of the tooth, since cutting is thus rendered more difficult, while there 
is up to the present no practical evidence of any advantage of this 
shape. He proposed a rectangular section of 1.7 by 1.5 mm with an 
optional radius on the corners. 'Mr. K. Geyer (apparatus manu- 
facturer) did not see any advantage in the shape recommended by 
'Mt. "S'inten. It was necessary more or less to radius the corners. 
Unfortunateh^ this meant duiiinishing the useful width of contact 
between the tooth and the ffim. Mr. Decaux considered it unneces- 
sary to make the tooth particularly wide on the face in contact with 
the edges of the perforation. Owing to the pull exercised bj^ the teeth 
on the film the latter wore and buckled at the parts in contact with 
the extremities of the tooth. The size of 1.7 mm appeared to him to 
be ample. It is, on the other hand, preferable to avoid contact on the 
lateral faces of the perforations with the sides of the tooth. ^Ir. De- 
brie (apparatus manufacturer) proposed that one should retain the 

36 Transactions of S.M.P.E., March 1926 

tooth width of 1.7 mm, leaving to manufacturers the option of radius- 
ing the lateral faces. Dr. Joachim did not think there was any danger 
to the film if one took the precaution of slightly radiusing the edges of 
the tooth. He did not see any disadvantage in the form of the tooth 
varying between the two limits proposed. Mr. E. Blake of Kodak 
Ltd., suggested that before finally deciding on the shape of the tooth 
it was needful to fix the shape and dimensions of the perforations. 
Professor Goldberg supported Mr. Debrie's proposal to adopt two 
shapes of tooth, the sections at the base being respectively a rectangle 
and that portion of a circle enclosed by two equal and parallel chords. 
He considered that the shape of the tooth should be standardized 
before that of the perforations owing to the extreme complication of 
the latter question. Supposing that the question of perforations 
could not be agreed upon it would be extremely annoying if the 
question of teeth could not be decided upon. Mr. Debrie remarked 
that three perforations— Edison, New type Pathe, and new type 
Kodak — are practically the same size in their rectilineal part. He 
insisted that the shape of the tooth should be discussed before the 
shape of the perforations, all the more because in the course of years 
projectors would have to pass films having these varying shapes of 

After an intervention by Mr. R. E. Crowther (Kodak), Mr. A. W. 
Kingston asked that the question of whether the shape of the tooth 
or the shape of the perforations were to be first decided should be 
put to the vote. By fourteen votes against eight, the Congress decided 
to fix first the shape of the tooth. 

In the name of the English delegates Mr. Vinten again proposed 
the section of the base of the tooth suggested at the beginning of this 
discussion. Mr. Debrie maintained his proposal for the two limits, 
high and low, for the shape of the tooth at the base, the rectilineal 
part of this section having a width of 1.7 mm. The Congress adopted 
this proposal unanimously. 

Mr. Vinten suggested that the section of the tooth on the plane 
of a diameter of a sprocket should show the sides making angles of 15° 
with the normals to the axis of the sprocket. Mr. Flinker and Mr. 
Lobel proposed to fix the width of the tooth at the top at 1.5 mm. The 
latter proposal was adopted. It was decided also that the profile of the 
tooth should be that already adopted by D.K.G.; that is, a profile 
limited by two arcs of 1.8 mm. radius normal to the working circle 
of the sprocket. 

International Congress of Photography — Clerc 37 

Third Meeting, July 1, 1925 

Mr. C. J. Brichta in the chair. 

Mr. A. W. Kingston read the following communication: 

As a representative of the Kine. Camera Men's Society of Great Britain I 
have been asked to affirm that this society fully approves of this Congress and the 
ends which it seeks to attain. May I say as representing the oldest incorporation 
of Cinematograph operators that in the important question of improvements in 
cameras and accessories it would be very desirable that manufacturers should get 
in touch with one another and with associations formed analogous to that which 
1 represent. We think that appreciable advantages should result from this in the 
general interest. Manufacturers would surely effect economies in time and money 
if before proceeding with alterations to existing machines or before creating new 
models they took the advice of operators. It is a fact that in the only branch of 
English production which is at the moment prosperous — the production of 
industrial and topical films — important improvements have been made within 
the last few years all of which have been suggested by operators, and I am sure 
that members of the Congress will be interested in examining several photographs 
which I have arranged on the table — photographs which demonstrate these var- 
ious improvements. There is still more progress to be made before we get the 
ideal camera, equally suitable for topical work and for the studio. A light camera, 
easy to load, permitting rapid substitution of interchangeable lenses, will be 
certainly assured of a hearty reception. The growing demand would inevitably 
lead to the scrapping of cameras now in use. The standardization of film cores 
would be also very desirable for the operators, and I also consider standardized 
perforations essential. High speed cameras extend their field of application from 
day to day. 

One word also concerning tripods: The lack of initiative on the part of manu- 
facturers in the supply of light legs, rigid and easily handled, is much regretted by 
operators. No progress has been made since 1910. 

I should hke also to suggest that a very useful step could be taken by the 
Congress in initiating the formation of an international federation of cinemato- 
graph operators which would offer to its members traveling abroad advantages 
similar to those which the automobile clubs ensure for their members. Operators 
who more and more have to work in foreign countries could be helped out of the 
numerous difficulties they encounter. Such an affiliation could certainly procure 
for them many advantages with regard to administrative formalities, customs, 
police visas, various authorizations, etc. 

On behalf of the D.K.G., Professor E. Lehmann agreed with 
Mr. Kingston's proposal; many operators belonged to this society, 
and Mr. G. Seeber member of the committee of the D.K.G., very 
willingly agreed to go into this question in Germany and study it 
with his society. 

Returning to the discussion of the shape of the sprocket tooth 
the Congress unanimously accepted the following proposal : 

38 Transactions of S.M.P.E., March 1926 

The thickness of the tooth at the base is fixed at 1.4 mm, +0.05. 

As regards 32-toothed sprockets, Mr. Fhnker observed that, 
provided the number of teeth in engagement with the film was Hmited 
to six, the same calculations for 16-toothed sprockets would apply 
in the case of sprockets having thirty-two teeth. Mr. Vinten con- 
sidered that there w^as no need to conform to the American recom- 
mendation of adopting different diameters for upper and lower 
sprockets, particularly as one would then risk error in reassembling 
after an operator had dissembled his machine. Mr. Marrette con- 
sidered that while in principle it might be preferable to adopt slightly 
different pitches for top and bottom sprockets, practically the wear 
of the film on sprockets running continuously is negligible. He 
proposed, therefore, to adopt for both sprockets the same circum- 
ferential pitch already adopted for the Maltese cross sprocket. Mr 
Debrie considered that the number of teeth oii top and bottom 
sprockets should be left to the decision of manufacturers, it being 
understood that sprockets shall be calculated on the same basis 
adopted for the Maltese cross sprocket. After an intervention by Mr. 
C. J. Fox these proposals were adopted. 

The agenda now called for a discussion on the perforation of 
positive film. Mr. Lobel on behalf of the French committee proposed 
the adoption of the new Pathe perforation; namely, the portion of a 
circle of 3 m diameter limited by two equal chords 2 mm apart but, 
with rounded corners. Mr. E. Schmitz objected that 65% of the 
world's production had adopted the new Kodak perforation, a rec- 
tangle measuring 2.8X1.98 mm with corners rounded to a radius of 
0.5 mm. Mr. Debrie observed that the differences between these 
perforations are fairly small. Mr. Marrette mentioned that in 1908 
Pathe's had adopted an enlarged perforation with rounded corners, 
and he was happy to state that the Eastman Kodak Company had 
now adopted a practically identical perforation, the lateral arcs simply 
being replaced by straight lines in the new Kodak perforations. Mr. 
Debrie proposed that the Pathe perforation and the Kodak perfora- 
tion should be retained simultaneously, which would not present any 
new difficulties since the two perforations were practically the same. 
He asked the representative of the Kodak Company, however, to 
bring to 2.0 mm the height of the perforation now fixed at 1.98 mm. 
Mr. Blake saw no objection to this modification provided it is accept- 
ed by the Society of Motion Picture Engineers during the period 
of six months. 

International Congress of Photography — Clerc 39 

Dr. Tappen mentioned that after the introduction of the new 
perforation by the Kodak Company the Goerz Photochemische 
Werke had tried to adopt this perforation for their films suppUed 
to the United States, but their customers had not received this 
modification favorably. He thought that the Society Agfa found the 
same difficulties ; up to the present customers having insisted upon the 
old type perforation. Mr. Geyer was afraid that there are several 
difficulties to overcome in making punches corresponding to perfora- 
tions with rounded corners, but there was no objection against leaving 
open the adoption of either perforation. Dr. S. E. Sheppard stated 
that the Eastman Kodak Company had entirely overcome all 
mechanical difficulties in the manufacture of punches. Further, it 
appeared to him that if suitable, limited dimensions were fixed, the 
shape of perforations could be left to the choice of those interested. 
Mr. Vinten proposed that the Congress should adopt as standards 
both the Kodak and Pathe perforation, but suggested that the ques- 
tion should be further discussed, say, in two years, possibly at the 
next Congress. It is hoped that by that time, in conformity with a 
decision taken at a previous meeting, new projectors will be manu- 
factured in such a way that sprockets may engage only six teeth with 
the film once the possibility of a reduction in the height of the perfora- 
tion will thus be in sight, w^hich will give the film greater wearing 

A tolerance of ±0.005 mm was proposed by Mr. Lobel on the 
height (2.0 mm) common to both perforations. Dr. Sheppard in- 
quired whether this tolerance related to the perforation itself or to 
the punch or the perforator. He considered that the height of 2 mm 
would only be accepted with a tolerance of ±0.02. Mr. Vinten 
objected that such a tolerance would be excessive in the case of 4- 
punch perforators, any errors on the punches being possibly in the 
same direction and thus exaggerated. At his suggestion the Congress 
decided that the height of the perforations should be 2 mm (measured 
on the punch) with no tolerance. 

After an intervention by Mr. E. Blake, who thought the tolerance 
allowed by D.K.G. excessive, and by the French committee on the 
question of the width of negative and positive raw stock, and after 
a discussion, the Congress adopted the following resolution: 

The width of negative and positive raw stock is fixed at 35 mm 

40 Transactions of S.M.P.E., March 1926 

On the proposal to fix the width of projector gates between 35 
and 35.1 mm, Mr. Blake and Mr. Decaux objected that the width so 
fixed was hardly sufficient. Notwithstanding the fact that after 
development and drying the width of the film was reduced to 34.8 mm 
allowance must be made for splices which both by reason of the pres- 
sure applied to the film and on account of slight inevitable defects in 
the alignment of the two ends, are always materially larger. There 
is no drawback from the point of view of lateral steadiness or of the 
gate being wider than the film; generally speaking, the film tends to 
run on one side of the gate; after a machine has been in use, even 
though the shafts may be perfectly parallel, there is always something 
sufficiently out of square in the neighborhood of the sprocket to give 
rise to play and lack of parallelism, which leads to the film running 
out of square on to one side of the gate. On the other hand, too narrow 
a gate has the objection of risking a break in the film due to the joins 
catching at the corner in passing the gate. Professor Goldberg re- 
marked that in a large number of projectors of German makes the 
width of the gate did not exceed 35.05 mm, but Mr. Schmitz observed 
that it is precisely on these projectors that accidents are most fre- 
quently occurring. Mr. Vinten mentioned that the "Simplex" pro- 
jector has no lateral guide for the film. On the proposal of Dr. 
Joachim the Congress decided : 

The width of projector gates is fixed at 35.10 mm +0.1 — 0.0. 

The French committee, having suggested that the pitch of the 
perforation of positive film should be determined after developing 
and drying under conveniently determined conditions, the American 
and English representatives spoke strongly against this innovation. 
Dr. Sheppard considered the proposal of the German committee on 
the same subject inacceptable, but the maximum shrinkage allowed 
in this proposal could be provisionally admitted as a basis for the 
determination of pitch of perforations. Mr. Blake on behalf of the 
Kodak Company stated that he could not accept the definition of 
maximum limit for shrinkage owing to the very different conditions 
under which stock is stored and methods of drying after developing 
by the various users and under different climatic conditions. Mr. 
Vinten considered that the manufacturers of the films should not be 
held responsible for variations in pitch which may manifest them- 
selves in perforated film, when the user submits this film to abnormal 
conditions or keeps it for a considerable time before using it. 

Mr. Schmitz stated that it was only for the past three years and 

International Coiigress of Photography — Clerc 41 

following the example set by the Pathe works, that manufacturers 
had normally supplied perforated film. Until this time the operation 
of perforating was carried out by the printer in accordance with his 
needs and on film whose tendency to shrinkage had already consider- 
ably diminished. The pitch of the perforation then remains reason- 
ably constant. Nowadays, on the contrary, the manufacturer of the 
film supplies to his customers, frequently a considerable distance 
from the factory of origin, perforated film which is not used until a 
long time after perforation, the film being perforated when the 
emulsion is fresh and still very moist. Under these conditions shrink- 
age is very accentuated, and the pitch is, therefore, considerably less 
than that of the new stock. There is also to be added to these circum- 
stances normal drying of the film during exhibition and local condi- 
tions which may influence the film in course of working, especially in 
very dry climates. To sum up, the film perforated by the manu- 
facturer so soon after sensitising does not retain its pitch, the shrink- 
age is all the greater when considerable time elapses between perfora- 
tion and use and when the film is kept in a hot or dry atmosphere. 

Mr. Decaux mentioned that to avoid these objections the 
Gaumont Company had kept to the old method of perforating the 
film themselves, keeping it in stock for a certain time in order that 
the perforating may not be carried out until after the initial period, 
during which film shrinkage is particularly rapid. 

Mr. Geyer recognized that if perforation is carried out by the 
manufacturer of films, only the raw stock can be standardized, but 
the manufacturer should guarantee that the shrinkage would not at 
any time exceed 2 per cent, 

Mr. Lobel stated that agreement seemed impossible on the sub- 
ject of shrinkage, and the consumer who had no confidence in the 
manufacturer's perforating had always the option of himself perfor- 
ating his own films. Mr. Blake mentioned that the Eastman Kodak 
Company was always pleased to supply unperf orated film. 

After this discussion the Congress decided that standardization 
should apply to all stock. 

At the request of Professor Goldberg and in conformity with the 
opinion expressed by Dr. Sheppard, it was agreed that the dimensions 
about to be decided upon should be established on the hypothesis of a 
shrinkage not exceeding 13^ per cent after 720 hours drying in a 
current of air moving at a speed of three metres per second at a 
temperature of 60° Centigrade and a relative humidity of 70 per cent. 

42 Transactions of S.M.P.E., March 1926 

Dr. Joachim remarked that one was accustomed to consider 
only the pitch (4.75 mm) between two consecutive perforations, 
when from the point of view of steadiness of projection it was neces- 
sary to consider the distance between two perforations separated by 
four spaces (19 mm) a distance which should be constant to within 
0.01 or 0.02 mm throughout the length of the film, failing which there 
was a great disadvantage of the variation attaining nearly 2 per cent 
in passing from one film to another, such films still running on 
sprockets which had already been defined. It was thus necessary to 
distinguish between these two tolerances, local and general. If this 
variation of 0.01 or 0.02 mm. on the height of the picture (0.05 to 0.1 
approx.) were not to be tolerated, it was necessary to consider the 
distance between two consecutive holes, and it would be sufficient to 
fix the distance of two holes separated by 100 spaces; that is, the 
length of 100 pitches. 

Professor Lehmann considered that it was necessary to standard- 
ize not only the distance between two successive perforations but 
also the distance between two consecutive pictures, for it is the latter 
which controls the steadiness of the picture on the screen. He pro- 
posed that in the same film the variation tolerated for this dimension 
should not exceed 0.02 mm. 

Mr. Debrie stated that the dimensions fixed for sprockets corre- 
sponded to a circumferential pitch of 4.712 mm; if a pitch of 4.75 was 
admitted for perforating the film at the average of its shrinkage (reck- 
oned at 13/2 per cent) it would have a pitch of 4.715 mm practically 
identical with that of the sprocket. He proposed, therefore, to fix the 
length of 100 perforations of raw positive stock at 475 mm + 1.0 mm — 

Mr. Blake stated that while admitting the probable maximum 
shrinkage oi 1^ per cent, the Eastman Kodak Company could not 
hold that in no case and no matter under what conditions the film had 
been stored should shrinkage be less than this limit. The maximum 
shrinkage of 13^^ per cent holds good only for the conditions of drying 
above specified. 

The Congress decided that the dimension of 10° perforations 
should be fixed for positive stock at 475 mm + 1.0 — 0.0. 

Fourth Meeting, July 2, 1925 

Mr. Vinten in the chair. 

Mr. Kingston presented and handed around some photographs 

International Congress of Photography — Clerc 43 

showing various improvements carried out by English manufacturers 
on topical cameras on the suggestions of the members of the English 
Kine. Camera Men's Society. He showed also some photographs 
showing the Proszynski's Aeroscope camera, driven by air compressed 
with a hand pump into a reservoir inside the camera, and which due 
to gyroscopic stabilization could be held in the hands while taking. 

In conformity with the English proposals the distance from 
centre to centre of the two rows of perforations on positive film was 
fixed at 28.15 mm+0.05-0.0. 

Before opening the discussion regarding the dimensions to be 
adopted for the negative film, Mr. Flinker remarked that the same 
16 toothed sprocket, the dimensions of which had been accepted for 
projectors, could be used for cameras, th6 only difference being in 
the centre distance between the teeth, which might be fixed at 28.2 
mm. The same milling cutter could thus be employed for cutting 
positive and negative sprockets. Mr. Geyer suggested that the dimen- 
sions of negative film should first be determined from which the sizes 
of sprockets could be deduced. The Congress supported this proposal. 

Mr. Vinten suggested that with the exception of the pitch the 
same dimensions and the same perforations (Kodak Pathe) could be 
adopted for negative stock as for positive, the Bell and Howell 
camera being the only one in which the old type negative perforation 
was necessary. 

Mr. Schmitz thought the Kodak Company must meet the views 
of apparatus manufacturers on the question of the shape and dimen- 
sions of perforations to satisfy the needs of the American market, the 
majority of which used the B. and H. Camera. They would have to 
continue to supply films with the old type perforations (sharp corners, 
height of hole 1.85 mm) and a pitch of 4.7499 mm. Mr. L. P. Clerc 
observed that an international standardization would not take ac- 
count of immeasurable dimensions, resulting from the conversion of 
fractions of the English inch to its metric equivalent. Mr. Flinker 
remarked that if Mr. Vinten's proposals were accepted, the French, 
English, and German apparatus manufacturers would be compelled 
to make alterations to their models, and there was no reason why 
the American manufacturers should be the only ones to refuse. Mr. 
Vinten drew attention to the fact that the conversion of existing 
models would not cost more than about two pounds. Dr. Sheppard 
objected that the Eastman Kodak Company and B. and H. had not 
been able to reach an understanding on this subject. Mr. Kingston 

44 Transactions of S.M.P.E., March 1926 

supported the proposal, adopting for negative film the same dimen- 
sions of perforations with the exception of pitch as for positive film. 
It was very desirable that cameras should be standardized in all 
countries. Mr. Vinten after a recent journey to the United States 
bore him out that this question was difficult to solve, but he consid- 
dered that a decision of the Congress would probably lead to B. and 
H. conforming to the general opinion to the benefit of all. 

Mr. C. J. Fox and Dr. Sheppard asked that it should be put to 
the vote. The Congress resolved unanimously: 

The shape of perforations and the distance from centre to centre 
of the two row^ of perforations shall be the same on negative raw 
stock as on positive stock. 

Mr. Flinker considered that the same pitch should be adopted 
for negative and positive film although several apparatus manu- 
facturers required a different pitch for the two films. Germany and 
the United States had already adopted the same standard for both. 

Mr. Vinten proposed to adopt measurements of 475 mm +2.0, 
— 0.0 for the measurement of 100 perforations of negative film. Dr. 
Sheppard objected that a pitch even so little larger than 4.75 mm. 
would not run on the B. and H. camera, and consequently the United 
States could not accept the positive tolerance proposed by Mr. Vinten. 

Mr. Decaux observed that before talking about the pitch neces- 
sary for the working of any given machine it would be advisable to 
examine for what reasons the pitch of negative film should be greater 
than that of the positive. Negatives are frequently stored for a con- 
siderable number of years, during which time the shrinkage continues 
to increase. On the other hand to consider only a fairly new negative 
that has already gone through the operations of developing and drying 
and has consequently already shrunk; no matter what type of printer 
may be used, it is certainly desirable that the pitch of the negative 
should correspond approximately to that of the positive stock in 
order to avoid running risk of movement due to the adhesion of the 
two films which militates against the steadiness of the projected 
picture. Mr. Decaux proposed that since 4.76 mm had been adopted 
as the maximum pitch for positive film, 4.77 mm should be fixed as 
the maximum pitch of the negative. 

Mr. Marrette considered that the film manufacturers have to 
satisfy the requirements of their customers, and it is up to the manu- 
facturers of machinery to come to some understanding. Mr. Schmitz 

International Congress of Photography — Clerc 45 

hoped that the decision of the Congress might have a useful influence 
on the apparatus manufacturers. 

Mr. Vinten's proposal was unanimously adopted with the excep- 
tion of abstentions on the part of the representatives of the Eastman 
Kodak Company. 

Mr. Marrette proposed that the Congress should choose some 
marked characteristic mark which should be stamped by manufac- 
turers in addition to their own mark on sprockets conforming to the 
dimensions adopted . He suggested the letter " S , " initial of ' ' Standard . ' ' 

Mr. S. H. Wratten and Mr. Clerc suggested that the date of the 
Congress should be included in the characteristic mark. Mr. Decaux 
objected that punching too long a mark risked interfering with the 
accuracy of the finished part. Mr. Marrette proposed to adopt as a 
distinguishing mark of sprockets conforming with specifications of 
the present Congress the letter "S" inside a circle. The design can 
be changed (square, triangle, etc.) in order to constitute in the event 
of any subsequent modification the distinctive mark of subsequent 
Congresses. This proposal was adopted by a majority. 

Mr. Vinten remarked that in cameras the sprocket serves only 
to guide the film, the movement being carried out by claws and that 
under these conditions the sizes of these sprockets could be abso- 
lutely identical with those of Maltese cross sprockets. 

On the proposal of Mr. Flinker supported by Mr. Marrette, the 
Congress decided that the sizes already adopted for projector sprockets 
should apply also to cameras, perforators, printers, and other aux- 
iliary apparatus. 

Dr. Tappen mentioned that the standardization of camera re- 
tort cores had been the subject of an enquiry in Germany and that 
agreement had not been established between apparatus manufac- 
turers. Mr. Vinten hoped that a proposal emanating from an inter- 
national Congress might have more authority and would perhaps 
enable the desired standardization to be effected. Mr. Ferrari laid 
stress upon the importance of this question of standardization to 

Mr. Newman proposed to adopt an outside diameter of 50 mm 
for cores. Mr. Marrette remarked that this diameter might prove 
rather large in the case of 120 m. film rolls. Mr. Newman stated that 
many troubles arose from the cores being too small in diameter, the 
friction functioning better with a large diameter than with a small, 
the difference between the initial and final diameters being propor- 

46 Transactions of S.M.P.E., March 1926 

tionately less as the diameter of the core is increased. Dr. Tappen 
thought that an exterior diameter of 50 mm could be adopted after 
an enquiry had been made among operators. It should be well under- 
stood furthermore that the projected standardization should apply 
only to professional cameras and not to small capacity amateur 
cameras. Mr. Kingston suggested that film manufacturers should 
specify whether they agree to deliver their films on standardized 
cores in order to permit of reverse work. Mr. Marrette agreed will- 
ingly on behalf of Pathe Cinema provided the shape of the cores was 
completely specified. Mr. Newman considered that if such a recom- 
mendation is made the manufacturers should adopt the recommended 
dimensions in their new models. 

Mr. Ferrari observed that as regards the internal diameter it was 
the diameter of the driving dog which was more important than that 
of the shaft. Mr. Kingston foresaw some difficulty in standardizing 
the centre hole of cores owing to the variations in the shape and 
dimensions of the driving shaft . After an intervention by Mr. Jourjon, 
Mr. Clerc remarked that if the largest of the diameters in use was 
adopted as a standard it would be easy to make use of intermediate 
bushings for each type of camera. 

Mr. Marrette suggested that the width of cores should be the 
width already fixed for the film. 

Mr. Flinker asked if recommended means of driving could not 
be proposed. The majority of members were of the opinion that a 
decision on this point should be left to the next Congress. 

The president put to the vote, and the Congress adopted, the 
following proposal: 

While reserving to a further Congress a definite decision, after 
further enquiry the Congress suggests that manufacturers should 
conform in the design of new models to the following recommended 
dimensions for cores: External diameter, 50 mm; Internal diameter, 
20 mm; width equal to that fixed for film. 

Mr. Kingston hoped that film manufacturers would regularly 
keep in stock film wound on the cores just specified; some of the film 
wound emulsion out; some with the film wound emulsion in, in order 
to avoid rewinding. The manufacturers represented at the Congress 
were agreeable to this. 

I Titer national Congress of Photography — Clerc 47 

Fifth Meeting, July 3, 1925 

Mr. A. S. Newman in the chair. 

The text of the resolutions agreed during the previous meetings 
drawn up by Mr. Fhnker and translated by Mr. Lobel was adopted. 

As regards the period of six months allowed before putting these 
resolutions into effect, the Congress adopted the following arrange- 
ments : 

The resolutions voted by the Congress shall be definitely adopted 
after a period of six months counting from the July 4, 1925, provided 
no opposition is formulated by national organizations taking part in 
the deliberations of the Congress. 

The centralization of such opposition was entrusted to an execu- 
tive committee of five members. The K.M.A. and the Society of 
Motion Picture Engineers should appoint their respective delegates 
to the committee, the other nations will be represented by Professor 
Lehmann (Germany), Mr. Brichta (Czecho-Slovakia), and Mr. Lobel 
(France), who will perform the duties of Secretary. 

In default of agreement by correspondence the members of this 
committee will meet in Paris to draw up the text of final resolutions. 

Sixth Meeting, July 4, 1925 

Professor Charles Fabry in the chair, assisted by Prof. J. Alber- 
totti and Prof. R. Luther, Dr. Slater Price, the chief Reporter, and 
the general Secretary. 

Mr. L. Lumiere suggested that a resolution should be taken to 
indicate the most desirable frequency with which the International 
Photographic Congress should be held. After interventions by Messrs 
Clerc, Crowther, Gaumont, Luther, Kingston and Ferrari proposing 
intervals of two to five years Mr. G. Labussiere proposed that the 
next Congress only should be decided upon and suggested in order 
to strike an average of the views expressed, to fix the date of it in 1928. 
On behalf of the English delegation Mr. S. Read supported this pro- 
posal, which was unanimously adopted. 

Mr. Slater Price suggested that the Royal Photographic Society 
would be pleased to invite the next Congress to London. Unanimous 
applause demonstrated that in this case the invitation would be 
received with general satisfaction. 

Mr. L. P. Clerc, chief reporter, remarked that the powers of the 
permanent committee would shortly expire, and it was necessary to 

48 Transactions of S.M.P.E., March 1926 

proceed with the nomination of a fresh committee to assure the pre- 
paration and propaganda for the next Congress, "'^t would not be 
sufficient to renew the powers of the previous committee on which 
many nations were only represented by a small number of members, 
especially by comparison with the large number of French members, 
to whom under the powers accorded to them the committee had had 
to entrust the organization of the actual Congress; he invited the 
members present to formulate proposals for the representation of 
their respective countries in the permanent Committee. 

On behalf of the English delegation Mr. S. Read proposed to 
enroll as Members of the Committee, Dr. Slater-Price, Acting Presi- 
dent of the Royal Photographic Society and at least three members 
to be appointed bj^ the said Society. 

Prof. R. Luther proposed to add to the German members of the 
previous committee (Professors Goldberg, Luther, Miethe, and Dr. 
von Rohr) Prof. E. Lehmann, acting president of the D.K.G. and two 
members to be appointed by the Society. 

Colonel Morisseaux, President of the Belgian Photographic Soc- 
iety proposed to add Messrs. Callier and Puttemans, members who 
were retiring, the acting President of the said Society and other 
members to be appointed by it. 

In the absence of the American delegates it was proposed to add 
to Dr. Mees, who was retiring from the committee, the presidents of 
the Optical Society of America and Society of Motion Picture En- 
gineers and members appointed b}^ either of these Societies. 

For Italy, Prof. Albertotti proposed to add to the retiring mem- 
bers Dr. Namias and Captain Clementi, Professors A. Gardasso, 
Senator Kingdom, Director of the Physical Institute of Florence, and 
Charles Bonacini, Director of the Astronomical Observatory of 

For Spain, there would be added to Mr. Garriga-Roca the acting 
Presidents of the Roj^al Photographic Society and the Photographic 
Union of Spain and their delegates. 

For Austria, Professor Eder and Professor Dolezal, retiring 
members, would be re-elected and would be joined by the acting 
President of the Vienna Photographic Society and its delegates. 

Sweden would be represented by the acting President of the 
Fotografiska Foreningen and other members appointed by this 

International Congress of Photography — Clerc 49 

The French Society of Photography would be represented by 
its acting Presidents, by various members appointed by it, and by 
the Secretarial members of the Sixth Congress. 

The national organizations of countries not mentioned above 
could be represented on the permanent Committee by getting in 
touch with the President or the general Secretary who would be 
ultimately appointed. 

The permanent Committee would retain the power of adding to 
its number any persons whom it was thought would be of assistance. 

To facilitate relations between members of the permanent Com- 
mittee a Secretary would be appointed in each country. 

If, as Dr. Slater Price hoped, the next Congress would meet in 
London the President and the general Secretary of the permanent 
Committee should be appointed by the Royal Photographic Society. 
The whole of these proposals were adopted unanimously, as was also 
the proposal made by Mr. Clerc to nominate as Honorary President 
General Sebert, the previous President. 


Alfred W. Abrams* 

TO DETERMINE the value of any means of accomplishing a 
result one needs to have clearly in mind the nature of the work 
to be accomplished. It is also advantageous to know quite 
definitely the fundamental principles involved in the application of 
the means employed. This is nowhere more true than in the field of 

We are spending in the United States large sums of money 
and a vast amount of energy upon what is called education in the 
belief, generally held, that every citizen should be fitted to enjoy as 
fully as possible the advantages of our social and political oppor- 
tunities and to meet the responsibilities that come to him. It be- 
hooves us to determine what constitutes true education. 

Definitions of education have varied in form, but they all 
directly or indirectly stress such things as organized knowledge, 
real experience, training, capacity for appreciation of cultural values, 
and ability to initiate action. Never do we find a claim set up that 
mere information constitutes education. 

Subject matter varies greatly in its significance for education, 
and of any given subject some parts are of much more consequence 
than others. Knowledge of the composition of a stick of dynamite 
may be very needful for certain persons, but it can not be so generally 
and vitally useful as an understanding of the principle of representa- 
tive government. 

The test of education is ability to make sound judgments, to 
initiate a course of reasoning, to apply knowledge to new uses, to 
react effectively upon data or conditions presented. Education is 
to be judged not by the number of items that have been presented 
and impressed upon the mind but by the changes the mind has under- 
•gone through its own exertions. 

While these statements do not furnish a complete basis for 
determining the educational value of motion pictures, they serve 
as starting points. 

* Director of the Visual Instruction Division of the New York State De- 
partment of Education, Albany, N. Y. 

50 " 

Educational Value of Motion Pictures — Abrajns 51 

The persons who are being educated through agencies main- 
tained for the purpose may be grouped into two classes: first, those 
attending a "school" of one kind or another; second, those whose 
education is being extended through organizations of various sorts. 
School exercises are graded', frequent, and thoroughly systematized. 
Extension acti^T^ties are less frequent, often intermittent, and gener- 
ally patchy in character. The attendant of a school has definite 
assignments of work to be done. For the other class, information is 
given, ideas are formulated, desires are aroused or intensified on 
special occasions, but little previous preparation is made, the indi- 
vidual does not participate in discussions and little formal response 
is expected. 

Educational extension is not to be ignored. In the aggregate 
it counts for much. For many persons it is the chief dependence. 
But in any consideration of the educational A'alue of picture expression 
it must be remembered that in A'olume and in importance school 
exercises far outrun those of all others that serve groups of persons. 

In what I have to say I am chiefly concerned with the problems 
of the school classroom. Insofar as a school undertakes to give mass 
instruction through auditorium exercises, its work is in character 
essentially the same as what I have classed extension activities. It is 
in the classroom where day after day for eight years or more of the 
elementary school and four years of the high school, not to mention 
the college and university, small groups are being instructed in a 
systematic, intelligently conceived course of studies, trained to think 
and given abundant practice in expressing ideas acquired. From an 
educational point of view it is necessary that our theories and practice 
of casual instruction shall fit into the larger features and purposes 
of the school program. 

There has been a tendency on the part of some to make absurd 
claims for pictures as a means of education; such as the shortening 
of the school course by several years, the possibility of learning with 
but little effort, and the unlimited range of subject matter that can 
advantageously be presented through them. 

On the other hand, conservative persons, including many edu- 
cators, have failed almost altogether to see the significance of picture 
expression when dealing with material things. 

We should all recognize that whenever we attempt to visualize 
objects for the fii'st time we must bring the organs of sense, chiefly 
the eye, to bear upon them or upon pictorial representations of them. 

52 Transactions of S.M.P.E., March 1926 

No other conclusion is at all tenable. If this fact can be established 
not only as a theory but as a working principle, the cause of visual 
instruction is won, and we can join hands with those who insist, on 
equally good grounds, that language is a better medium for expressing 
relations, ideals, general truths, and metaphysical conceptions. 

With these introductory statements, already too far extended, 
let us consider the place of motion pictures in the school program. 
In doing so it will be necessary at certain points to compare them 
with "still" pictures. 

Let me say at the outset that I have no desire to quarrel with 
motion pictures. I am as desirous as anyone to discover their true 
relative place among the various means to be profitably employed in 
securing educational results. I have no doubt that for certain purposes 
and at certain times they are decidedly useful. But I cannot avoid 
the recognition of relative values. 

The chief field for picture expression is that of the material 
world. Only indirectly do pictures represent anything but objects. 
The mental process by which we perceive objects and combinations 
of objects and apperceive their meaning is called observation. This 
is much more than looking at the objects or their pictorial representa- 
tions. The process is complicated. It requires close and definite 
analysis of details, necessitates time for a recall of previous experi- 
ences, involves association of ideas, and includes judgments as to 
significant relations. 

The motion picture presents a succession of objective phenomena 
with too great rapidity to allow these steps to be taken except by a 
person who is alread}^ thoroughly familiar with the phenomena 
presented, and even such a person sees and recalls only enough to 
pick up and carry along the story that is being told. 

The motion picture serves as a very good means of testing ability 
to observe. But before testing there should be training. The ability 
to observe does not come by intuition. If observations are to be 
made to a purpose, there must be a selection of features that are 
worth attention and a passing over of what is non-essential. It is the 
function of the teacher to create in the mind of the learner standards 
for observation and to direct practice. It is not enough that the pupil 
snatches from the passing pictures certain scattered impressions. 
There is need for pointing out what the learner is failing to see. It is 
not of much use to do this after the picture has passed from view. 

Educational Value of Motion Pictures — Ahtams 53 

The test of what a pupil is gaining from a picture is his ability 
to express what he is acquiring. As a means of teaching there is much 
less value in the report of the pupil given after the picture has been 
removed than in his statements made while the picture is still before 
him. In the latter case there is opportunity for the teacher to build 
up the power that is found deficient. In this respect there are obvious 
advantages in the still picture. 

Unless the phenomena represented by the picture are so simple 
as to offer no real problem, discussion is necessary to learn their full 
significance. If discussion must be based upon such partial observa- 
tions as learners are sure to have made, the full value of the picture 
cannot be gained. To extend the range of observation and interpre- 
tation is the very purpose of the classroom exercise, not primarily 
for the sake of the information or knowledge to be gained, but to 
increase the ability of the pupil to do this sort of work. The motion 
picture does not encourage such extension of observation and inter- 

In the whole matter of training in observation, the still picture 
offers superior advantages except in observing a single aspect, 
namely, that of motion. The only other aspects of objects that can 
possibly be perceived through the sense of sight are size, form, 
position, and color. All these are static. There can be no possible 
advantage so far as observation is concerned in having the object 
in motion. It is necessary to a full observation that the picture 
remain before the eye for a considerable length of time. Take the 
matter of size. Size cannot be expressed except in terms of some 
unit of measure. An appreciable amount of time is required to 
select a familiar and practicable basis for comparison and determine 
the quantitative relation that exists between the object and the unit 
selected. As to color, not all reds, for example, are alike. There are 
differences in hues and shades. Look along a street where there are 
half a dozen brick buildings to find, if you can, two that are alike in 
color. This is a very simple case. But observation that notes differ- 
ence in these static aspects is something that is required for success 
and enjoyment in every walk of life. 

The supreme field of the usefulness of motion pictures is the one 
in which motion plays a large and essential part. Understanding 
this, we have one guiding principle for making and for using this form 
of picture. 

54 Transactions of S.M.P.E., March 1926 

But even here there is opportunity for comment. Movements 
may be resolved into a Umited number of types, and when the learner 
has become familiar with a certain t^^pe it is not necessary for him to 
see actual motion to visualize what takes place. A still picture of a 
team of horses tugging in the harness is sufficient to call up the 
needed mental picture of action and the probable result. 

I have already suggested the part played by the teacher in 
visual instruction. There is little place for the teacher in the use of 
motion pictures. Indeed, some enthusiasts have been so unwise as to 
claim that by using motion pictures a considerable part of the teach- 
ing force can be eliminated. The attempt to talk while a motion 
picture is running can not be a large success, for attention is divided 
between seeing and hearing. To precede or follow a showing of a 
picture by verbal statements is not visual instruction, even if it 
may lend some aid to it. 

The use of motion pictures is related to the problem of attention. 
Attention is of two kinds, voluntary and involuntary. Motion 
pictures appeal chiefly to the latter. One impression after another 
beats upon the retina. The pupil looks to see what comes next, not 
to analyze what is being presented. At least he can only apply a 
part of the ability to analyze previously acquired in various wa3^s. 
Involuntary attention depends upon what comes from without. 
Voluntary attention depends upon an inner reaching of the mind 
to gain understanding. The ability of the pupil to direct and hold 
attention upon an object or problem is the mark of a trained mind, 
and this ability it is the function of the school to develop. I do not 
believe motion pictures are as well calculated to accomplish this result 
as still pictures are when used by a competent teacher. 

It is claimed that motion pictures are interesting, hence useful 
for school exercises. Interest is a result, not a means. The new born 
babe is not interested in anything. As he acquires experience with 
his environment and learns that certain things contribute to his 
enjoyment or success, an interest in them is established. Interest 
that is worth anything leads its possessor to put forth sustained 
effort to secure a desired result. One is interested in whatever one 
knows thoroughly or can do well and continues to find advantageous. 
Interest may begin with involuntary attention, but it assumes 
importance only when it calls for further effort. It is admitted that 
still pictures require more effort both by the teacher and the pupil, 
but the result of this effort is a growing interest. My observations 

Educational Value of Motion Pittures — Ahranis 55 

lead me to believe that after the novelty of so-called educational 
motion pictures has worn off the interest of pupils in them becomes 

The field of motion pictures is prmiarily entertainment and not 
education. The factors of entertainment are novelty, rapid change, 
variety, striking features, frequent surprises. In general, these 
factors do not contribute largely to education; on the other hand, 
they often interfere with it. It does not seem likely that educational 
films for the schoolroom will be made that will long satisfj" pupils 
who have attended motion picture theaters. To them motion pictures 
come to mean something quite different from what the school program 
requires. Even children are not insensible to the fact that there is a 
time to work as well as a time for relaxation and freedom from 
sustained effort. 

Since pictures present onh^ the objective facts on which the 
higher mental processes depend, the}^ are only starting points in 
education. Above material phenomena rises the whole range of 
human thoughts, ideals, emotions, and actions. The latter are best 
expressed and understood through language expression. The develop- 
ment of subjective mind depends at the outset upon experience with 
objective matter. The tests of education I mentioned at the outset 
can be met only by the mind that has digested and assimilated and is 
ready to react upon with precision and certainty the sense percepts 
gained through pictures. These processes involve concentration and 
close mental effort and are aided by the stimulus and guidance of a 
competent teacher. 

A motion picture to succeed at all must be complete in itselt 
and carry its message without the aid of a teacher. On the one hand 
it does too much for the pupil in that it presents its story with full- 
ness; on the other hand, it does too little in that it does not exact a 
mental picture created by the pupil through his own eft^orts. There 
is too much presentation and too little self expression. 

There are mechanical and administrative difficulties in the way 
of the general use of motion pictures in the classroom. ^lost teachers 
are not likely to operate projectors successfulh^ To depend upon 
special operators to appear at stated intervals is not good administra- 
tion. To be of service in carrying out a course of study, pictures are 
needed for use at the moment the topic is to be taken up. Showing a 
picture some days or weeks later must prove to be unsatisfactory. 
The use of pictures must synchronize with a pre-arranged program. 

56 Transactions of S.M.P.E., March 1926 

It must remain exceedingly difficult and expensive to place motion 
pictures in the classroom precisely at the time needed. 

The occasional use of motion pictures may have value in intro- 
ducing a certain amount of variation from the somewhat uniform 
school program. A different means of approach offers a new stimulus 
that helps to accomplish the ends in view. The main dependence 
in education, however, must be upon something better than novelty. 

As to the matter of the cost of using motion pictures in schools 
I need not speak at length. The fact must be faced that at the present 
time the amount that is expended annually by a particular school for 
equipment is small. The cost of motion picture equipment including 
film service is now high. It is not probable that it can be materially 
reduced. My own investigations show that boards of education 
seldom include in their budget an item for such pictures. The use 
of motion pictures is generally unofficial. If they are provided for at 
all, the money for them is furnished by parent-teachers associations, 
is raised by teachers and pupils, or is secured by paid admissions. 
Such a procedure can not be far reaching. Further, it is well to 
consider whether the money that is expended would not bring larger 
results if invested in still pictures and adequate equipment for their 

Motion pictures may serve a useful purpose in furnishing an 
initial stimulus for study. They may also present in story form the 
ensemble of static phenomena that have already been perceived 
through other means. They may thus play an important, though 
subordinate, part in a general scheme of education. I believe it would 
be of real advantage to those who are interested in promoting the use 
of motion pictures to recognize the limits of their usefulness and to 
proceed at once to assemble for co-ordinate use the most significant 
still pictures procurable in the form of prints or slides and be 
zealous to secure their systematic use. Up to the present time millions 
of dollars have been spent in attempts to produce educational motion 
pictures. Most of this investment has been unprofitable. It should 
be easy to see what a fraction of this expenditure would bring if 
distributed wisely and proportionately over the whole field of visual 
aids to instruction. 

It is often said that there is already an adequate supply of still 

pictures. This is far from the truth. Most of those in use are of little 

significance for school work and are of very poor quality. Further, 

. the time is at hand for giving less thought to extending the circulation 

Educational Value of Motion Pictures — Abrams 57 

of pictures and much more to determining the character of the 
results that should be secured from them and what preparation the 
teacher must make to do her part in accomplishing such results. The 
wide extension of visual instruction will come when it has demon- 
strated its usefulness and practicability and not before. 


Mr. Cook: It is with a good deal of diffidence that I venture to 
discuss the very masterly paper that we have just listened to from 
Dr. Abrams. It is in such marked contrast to the papers we have had 
previously on the subject that it comes like a dash of cold water. 
It would be presumptuous in me to question a great many of the 
statements of Dr. Abrams, although I am not in accord with them. 
Dr. Abrams has had an unequaled experience in connection with his 
branch of the New York State Board of Education for a great many 
years. We are all familiar with the work he has done. 

I think that much of Dr. Abrams' criticism is justified by the 
status in the use of so-called educational motion pictures, but some- 
times we may make a mistake in considering only the present status 
of an art rather than visioning its possibilities under improved con- 

It so happens that it has been my modest part in the motion 
picture industry to be connected with a company which, for nine 
consecutive years, has furnished motion pictures under contract to 
the New York City Board of Education. Our experience has corrobo- 
rated Dr. Abrams' remarks regarding the average teacher's mechani- 
cal and business ability. Dr. Abrams has expressed it very mildly. 
We have sent out trouble men only to tell the teacher to insert the 
lamp in some cases and in others to turn the switch. There are 
many mechanical troubles which can be obviated in improved pro- 
jection equipment. There are now prefocusing lamp bases which 
will eliminate trouble in this respect. 

Probably much that Dr. Abrams has said about the present 
available motion pictures is justified. He is not enthusiastic, however, 
about slides. Yet the slide industry has been many years in develop- 
ing and has reached a relatively higher development in education 
than has the educational motion picture. 

Our experience with the Board of Education was that we had 
just about as many opinions with regard to the merits of a motion 

58 Transactions of S.M.P.E., March 1926 

picture as we had principals and teachers who viewed them. The 
lack of unanimity was startling. A picture which would be accepted 
with acclaim by one school would be severely criticized in another. 
The principal difficulty in the past has been an attempt to adapt 
existing entertainment or instructive pictures to educational use. 
That has been about all that the educator has had to work with, 
and they were not at all suited to pedagogic use. 

As many of you know, several manufacturers are developing 
narrow width motion picture equipment that is much more economi- 
cal, more easily operated, is free from many of the drawbacks of the 
professional size of film, and would seem to be more ideally adapted 
to classroom instruction than anything yet available. 

Co-operation should be worked out between the textbook author 
and the film producer so that the school would own and show films 
prepared in collaboration with the textbook. This would seem to 
overcome a great many of the difficulties and problems outlined 
by Dr. Abrams and which only seem at present insuperable obstacles. 

Going into details, color, while not commercially available, 
is apparently well within the possibility of the near future. It will 
enormously enhance the value of certain forms of educational films. 
For that matter, most of the textbooks are subject to a similar 
criticism in the lack of color in the illustrations. 

The objection to novelty in the use of the film hardly seems to 
be a very strong one. If we can arouse the interest by novelty, it 
would be an advantage. 

I agree with Dr. Abrams on the undesirability of the teacher 
talking during projection. It is impossible for the student to watch 
a picture carefully and listen to the teacher at the same time. It is 
better to do all the talking before, or after, or stop the film. You all 
know how disconcerting it is to hear some one in front of you in the 
theatre talk about the picture. A child's mind is not so well able to 
cope with this double attention as ours. 

Again, Dr. Abrams deprecated the use of films because they were 
not self-sufficient, and I do not see that they should be considered 
as self-sufficient. I think their purpose is to correlate with the 

Dr. Abrams: I intended to say that they are too nearly self- 
sufficient. They present to the mind all the facts; I want something 
left foY the student to construct for himself. The architect sees the 
building before his drawings are made. It is this constructing process 

Educationa] Value of Motwn Pictures — Ahrams 59 

that is vital. You cannot plaster education on the mind. You cannot, 
with pictures alone, make sure you are getting the mental reaction 
you are after. We should leave something for the child to do and 
compel him to go to books to read. 

Mr. Cook: The fact that so much has been spent without 
appreciably beneficial results in the field of educational motion 
pictures should not deter us from continuing efforts in the same 
direction. We are all familiar with the recent casualties in air naviga- 
tion, with the tremendous expense preceding it, and with the loss 
of life, but I do not think there is any doubt that air navigation will 
continue. Should we not draw beneficial conclusions from past 
experience and put those experiences to advantage in moving on to 
the successful use of what I believe most of those present agree is one 
of the great educational media of the future? 

Mr. Beggs: I think the reason people well versed in book 
learning are apt to be killed in traffic is that they are too good at the 
"static stuff." Life is not static, it is moving rapidly. We should give 
children ideas of moving things, and for this how could it be done 
better than with the motion pictures? 

Mr. Richardson: The one thing that struck me forcibly was 
your asserting that the teacher should not talk during the showing 
of a motion picture, and that the action is too rapid for the student 
to assimilate the proposed lesson. You have made a broad assertion. 
Teaching by stereoptican slides you admit has value. What would 
you suggest as the proper way to go about securing a really adequate 
set of still pictures? 

Dr. Abrai^is: I did not mean to convey the idea that when a 
motion picture is presented it does not yield certain information, 
and, of course, it must start some reaction. I meant to say that 
with any mere presentation you are chiefly testing what is already 
in the mind of the observer. You need something more. The teacher 
should give the pupil a more exact training in "how to observe," 
which involves eliminating non-essentials. If I find a teacher asking, 
"What is in this picture?" I say her method is wrong. I am using 
the picture to put over a particular idea. I read a book for a particular 
purpose, and am a poor reader unless I can skim over the page until 
I reach the paragraph I want and pick what I need out of it. Now, 
I am expecting the school is going to give the student this train- 
ing, not mere presentation. Still pictures will not do much if they are 
merely put on the screen and looked at. 

60 Transactions of S.M.P.E., March 1926 

A picture should be a direct challenge to pupils. Most people 
do not know how to observe. Take, for example, the matters of size 
and form of objects. ° I was telling somebody here about the use of a 
picture of a coffee tree. The teacher had the pupils talk about the 
coffee industry to show what they had learned. When one little girl 
was talking I said: "Mary, tell me how big this coffee bean is that 
you are talking about." She didn't know. I said finally: "Name 
some fruit that grows around here that is like coffee." She looked at 
me and said: "Cucumber?" There is too much of that sort of thing. 
Motion pictures would be fine if used along with other means of 
developing these static elements. We are not after the picture on the 
screen but the mental picture that is built up in the mind of the 
observer. We must get that kind of picture, and when static elements 
are important, we must observe those elements. In working out the 
details of the coffee industry, you could advantageously put on a film 
showing the operations. The motion picture tells a story; it is good 
for narrative, not for description. 

I should like to work with somebody interested in motion 
pictures who would recognize that you must have something besides 
showing motion. I should like to find some one who would put a 
fraction of the money into still pictures that is going into motion 
pictures. You say it will not cost much to provide motion pictures. 
I wish you would tell me how much it would cost an average school 
in a town of two thousand inhabitants to provide enough to scratch 
the surface of this course of study. 

Mr. Cook: They don't exist yet. 

Dr. Abrams: But if they did; how much money do you think 
the schools should put into motion pictures? 

Mr. Cook: I answer that by saying, would you go to an archi- 
tect and expect him to answer you at once if you asked him how much 
it would cost to build a house? 

Dr. Abrams: A firm sells a set of lantern slides for $300; 500 
slides in teaching various subjects do not go far, and I predict the 
time will never come when any considerable number of schools will 
have in their own organization any large supply of pictures. The 
problem is one of circulation. Pictures would lie idle too much of 
the time. In this country there are at least forty or fifty bureaus 
acting as distributing centers. Supplying these distributing centers 
with the right material in sufficient quantity for them to pass on to 
schools and organizations would be a good business. 

Educational Value of Motion Pictures — Ahrams 61 

While you might put a hundred films in a town like Roscoe, 
what would be the condition of them at the end of the year? Schools 
do not know how to keep them at the proper humidity and to handle 
them properly. Can schools advantageously own lantern slides? No. 
One city recently spent about S8000 in buying lantern slides. Indi- 
vidual schools bought them largely from funds raised by selling old 
rubbers and newspapers — 500 or 600 slides in a set — the same set in 
each school. The money expended could have been better used for 
equipping classrooms with projection apparatus. Each of the schools 
in this case could receive annually for use when needed, free of 
charge, at least 10,000 slides from the State collection. A topic is 
taken up in one school once during the year. There must be a scheme 
for circulating visual aids to instructions. 

Mr. Richardson: You made the assertion that you had seen a 
great many sets of slides, but they were all valueless in school work. 
There apparently have been mistakes made in the production of 
slides; could you suggest how sets of slides having real value in 
educational work might be produced? 

Dr. Abrams: Most of the pictures offered us have been made 
from the tourist point of view. Not many of the things we see on 
a tour to Europe are what the schools want for geography. I want 
to know what a country looks like. I should like, for example, to 
give our boys and girls in New York a mental picture of what the 
western plans of the United States look like. I cannot get anybody 
to photograph them. A man who went on a long trip across the 
African plateau told me when he came back there wasn't anything 
there to photograph. "Why, there was nothing but a big flat plain," 
he said. And I said, 'Tf that is the characteristic feature of that 
country for hundreds of miles, why didn't you show^ it?" Most of 
the people who go out, even if they are good photographers, don't 
know the subject photographed. Others go out knowing everything 
about the subject but don't know how to manage a camera. 

Another thing: these commercial houses putting out slides 
don't want to pay much money. You cannot get good pictures and 
adequate organization of them unless you are willing to pay some one 
who has a definite idea of what they are for. When a concern is 
filming a subject for motion pictures, it would be a small job to make 
a parallel collection of still negatives. The New York State Depart- 
ment of Education would not collect negatives and work out titles if 
it could go to the trade and buy what it needs. 

62 Transactions of S.M.P.E., March 1926 

Mr. Denison: A gentleman recently came into this meeting who 
has had great experience in photographing pictures all over the world, 
including most of the Burton Holmes pictures. Mr. Cowling is here, 
and I think he could throw some light on educational travel pictures. 

Mr. Cowling: I might say that you can't afford to make still 
pictures. There is not enough demand to pay for them. I say that 
after almost starving to death trying to make a living out of it. 

The question of subject is the main item, and it wouldn't pay 
you to go into Central America with a still camera because you find 
that many stills that you can make are not better than you can buy. 

Dr. Abrams: I cannot find one-tenth of those I want. I have 
looked in vain to find good pictures for the raising of dates on the 
north coast of Africa. 

Mr. Cowling: It would cost about V500 to do one country, 
taking into consideration a long trip covering several countries. 

Dr. Abrams: But a man going out there might say: "When I 
find a good tree loaded with dates, I am going to make two, three, four, 
ten negatives and dispose of them to different parties. 

Mr. Cowling: You must make a motion picture first if you 
want to make expenses out of it. 

Dr. Abrams: I want to awaken an interest in all people to 
carry along with the motion pictures the still pictures and build 
up the whole scheme of visual instruction. 

Dr. Sheppard: We have very greatly appreciated Dr. Abrams' 
talk and his discussion of the relation of the still to the motion picture, 
but we are at present considering motion pictures rather than stills. 
The most important thing Dr. Abrams has said was in his initial 
points on the essentials of education in the early stages. He disclaimed 
considering the motion picture in higher education. He is dealing 
with education in the early stages, or primary education. 

Now, in the field of higher education I think we can foresee the 
kind of picture we want. In higher education, and in those phases 
between higher education and research — and the research man is 
always educating himself — the function of the motion picture is in the 
analysis of motion; it is not so much moving pictures as pictures of 
motion. Motion we represent to ourselves, because we cannot under- 
stand it, by a series of positions. That is not the true way in which 
things happen, but it is the only way we can form a concept of 
motion. Motion study has taught us much concerning manual 
operations and about complicated things like the gait of a horse; 

Educational Value of Motion Pictures — Ahranis 63 

I once saw a motion picture of a pigeon after the left hemisphere of 
the brain was removed, which has no meaning for me but filled the 
pathologists who were studying it with enthusiasm and from which 
they presumably learned something. These are simplified themes, 
and it is understood that these people select out the items they are 
going to treat. In the study of motion in an explosion engine the 
motion picture is being used and in countless fields of that type, 
and the selective element is always present. It is upon the study of 
pure movements, the problems of velocity and acceleration, that some 
concentration should be made by the author who is working for visual 
education. That demands, however, a different type of equipment 
or a modification of equipment. It will need the slow movie, and the 
possibility of stopping for stills and the explanation and discussion 
between teacher and pupil. I wish to suggest that we think along 
these lines and do not proceed on the idea that it is enough to present 
a series of pictures which merely lull the senses for the time being. 
You can evoke magnificent visions by drugs, and you can drug the 
senses through the eye, but no one would advocate that as a method 
of education. 

We cannot get away from the psychological analysis of educa- 
tion, as Dr. Abrams has emphasized. I am sure that the application 
of motion pictures to education will be a flivver if we don't bear this 
in mind. I do not feel that what Dr. Abrams has said is against the 
use of motion pictures in education; I think it is merely a guide to 
the right way. 

Dr. Abrams: There has been a tendency to make the films 
five hundred or a thousand feet long, and if you analyze them, you 
will find from 25-60 per cent of the film is still. I should eliminate the 
still parts. Why not, when you want to show the form and size, use 
still pictures and run a short film to present movement? Stopping a 
motion picture dofes not give you the same effect as a still picture 
made carefully for definite purposes. If you photograph something 
as a still and select the position to give the most telling view and 
work under favorable light conditions, you get a better result. 

You are right that I did not come here to condemn motion 
pictures, but I can tell you that you cannot do everything with 
either motion pictures or with stills; each has its purpose and its 

Mr. Richardson: I think you gave the answer to the whole 
thing in that coffee illustration, as I understood it. The thing to do 

64 Transactions of S.M.P.E., March 1926 

would be to use the stills to explain the size and the view of the 
coffee bean, followed by a motion picture showing the process of 
growing and harvesting the coffee. 

Dr. Abrams: That is all there is to it. 

Dr. Hickman: During the past five or six years I have been 
teaching and lecturing with and without the use of the projection 
lantern, and my opinion, for what it is worth, is that there are a 
thousand and one ways in which motion pictures can be useful for 
teaching purposes and an equal number of ways in which they are 
certainly not worth their expense. 

There are two processes involved in imparting knowledge : first, 
you may take your student to the water, and then you have to make 
him drink. Projecting motion pictures before him might be described 
as taking him to the water, but whether he drinks or not is dependent 
on his own mental effort and possibly the insistent voice of the 
teacher. For my own lectures I had two or three hundred slides, 
many of which I gave up because the students went to sleep. The 
knowledge was so easily displayed that it evoked no interest. The 
things it was absolutely necessary for them to learn I wrote laboriously 
on the blackboard, and they copied them equally laboriously into 
their notes. This applies not only to figures and tables but to drawings 
also. The lesson was learned because we both put an effort into it. 
Dr. Ingold of Leeds University has often said that lectures teach 
nobody anything except the man who lectures, the man who takes 
the pictures, and the man who makes the slides. While probably 
neither he nor I really agree with such a sweeping generalization, 
there is a very great deal of truth in the suggestion. 

Surely the true usefulness of motion pictures lies in the portraying 
of motion; that is, in presenting something to the student which 
can be shown him by no other mechanical means known. 

Dr. Abrams has said that the most important thing to visualize 
before the students is the size, quality, texture, and environment 
of the object in question. He suggests motion pictures do not do this. 
I suggest, on the other hand, that a properly prepared picture will 
do this better than anything else. He says a picture of the coffee 
bean conveys no idea of the size or the hardness of the bean. Had 
that same coffee bean been shown in a squirrel's mouth an idea both 
of the hardness and the size would have been shown in relation to 
a known object, the squirrel. Suppose I were to give you the quanti- 
tative data of a giraffe, saying that it is so many feet high and that 

Educational Value of Motion Pictures — Ahrams 65 

its neck projects at such and such an angle. Has that given you an 
idea as effective as a picture of a giraffe with a man standing some- 
where near to scale him and give the correct impression of size? 

The tirade which has been lodged against motion pictures and 
pictures in general for teaching purposes is surely that these pictures 
have been badly taken and improperly presented, that those taking 
the pictures are ignorant, and that the whole process of the pictorial 
recording of knowledge is bad from beginning to end. I wish to protest 
that this need not be so; the value of these things is simply what you 
make them, and their use in teaching the effort you put into them and 
the skill with which you present them. 

Dk. Abrams: I think you will agree there was nothing in Mr. 
Rogers' paper contradictory to what I said, but I suspect you like 
his paper better than mine because he talked in your favor, and I 
seemed to talk against your interest. Yet, I can see that you men 
realize that we are trying to get at the fundamental basis of this 
matter, and I hope I have not done you any harm. It is what the 
individual learner does that counts. You cannot look once at a 
picture you have never seen before and tell all there is in it. You must 
approach it from different angles. That picture is asking you a lot of 
questions, and any picture, whether still or in motion, is not going to 
accomplish much unless it gets mental reaction from the person who 
is trying to study it. In the field of entertainment it is different. 
There are educational extension activities which are not very serious, 
but they offer some stimulus and people have gone out benefited. 
They want something rather relaxing and something that calls 
back what is in mind. An illustrated lecture may have some value, 
and a motion picture may give stimulus, but only when you have 
discussion and interchange of mind and mind are maximum results 

President Jones: In reply to Dr. Abrams with regard to the 
suggestion that Mr. Rogers' paper may please us more than his, 
I think that is not necessarily the case. We have all felt that the 
present application of motion pictures to educational work is not 
altogether satisfactory, and we want to find out what is wrong with 
the present method of using them. He has told us of some of the 
faults. Knowing what the troubles are, we can try to find a remedy. 


Rowland Rogers* 

SEVERAL years ago our Society invited me to read the paper on 
"Can the movies teach?" I did. Then I ventured the assertion 
that there were few or no genuine educational motion pictures. 

Times change. We progress. Now I venture the assertion that 
there are some genuinely instructive pictures. By this I mean pictures 
that have been classed as "pedagogic," whatever that may mean. 
Strictly, "movies for teaching" are those suitable for use in the class- 
room or assembly hall to supplement or correlate definitely with 
existing courses of study given in schools. 

Recently I sent a questionnaire to a number of directors of visual 
instruction in the larger city schools and also to a number of state 
universities which are supplying motion pictures to schools in the 
smaller towns and cities. The list of films which they use for teaching 
is quite large. The following films received several votes each as 
being among the five best: "Hat's Off," "How Life Begins," "Milk — 
Nature's Perfect Food," "Inside Out," "Lumbering in the North 
Woods." I have brought one of these films here today and propose 
to show it to you. This is the best way for you to find the answer to 
the question, "Can the Movies Teach?" No matter how brilliant 
may be the oratory of your speakers and no matter how persuasive 
may be the logic of their words, we still face the age old proposition 
that "seeing is believing." This brings me to the theme of our dis- 
course and the first point I wish to make. 

There are two principal ways to express ideas: (A) One is by 
means of sounds. As we are not dealing here with the communication 
of ideas by means of sound, we pass over quickly the entire subject 
of the language of the spoken word. (B) By means of pictures. No 
student of history has any doubt that the picture language was of 
very early origin and that picture writing preceded what we call the 
real writing of today. Words are used as a means of visuahzation. 
The direct development of picture writing was the use of the picto- 

* Vice-President, Picture Service Corporation, New York. 


Movies for Teaching — Rogers 67 

graph and the ideograph. Xext, there doubtless developed a system 
of sjdlable writing to be later followed by alphabet writing, and so, 
during the course of centuries, there developed the language of the 
written word. There seems little doubt that writing is a child of 

In the preface to the Alerriam Edition of the Webster Dictionary 
is the following interesting statement: 

Xoah Webster was inspired to write a dictionar}' for his fellow Americans, 
because a dictionary, more than anything else, in the range of devices and in- 
strumentahties for culture, should supplement the school and the elementary 
spelHng book and should make the population eye-minded, so to speak, as well as 
ear-minded, .... make the common language \dsible to the eye as well as audible 
to the ear, .... 

The movie maker (today's Webster) is adapting the age old 
picture language to teach in school, church, and factory. 

I do not need to come here with a brief in support of the use of 
pictures and especially photographs as a means to convey' ideas. 
Arthur Brisbane (an editor should know), has been quoted as stating 
what is really a repetition of the old Japanese Proverb, "One picture 
is worth a thousand words.'' I am informed that the circulation of 
the New York Times, which, in its daily edition, relies almost entirely 
upon the language of the printed word, has a circulation of about 
350,000. This paper was established nearly seventy-five years ago. 

On the other hand, the New York News, a tabloid newspaper, 
established about five years ago, has a daily circulation of around 
900,000. Pictures need no support to prove their value. 

You, as members of the Societ}^ of Motion Picture Engineers, 
know that there is no such thing as a moving picture. A moving 
picture is a blur. All that we see projected on the screen is, of course, 
a series of still pictures projected so as to simulate life and acti-on. 

The main function of the motion picture is to express pictorial 

Still pictures well represent still life. A mountain in its majesty 
is well visualized by a "still," but a still picture of a motionless hunter 
feverishly chasing a motionless mountain goat is an anomal\\ You 
can multiply indefinitely for yourself the illustrations where motion 
is essential, especially if you are a fisherman, a golfer, or a tennis 

The, still picture at times presents an untrue picture, lifeless, dull, 

68 Transactions of S.M.P.E., March 1926 

Movies are the art of jDictorial movement. In movies all the 
principles of the still picture lives. Line, light and dark remain. Color 
prevails with the addition of action. The movies do not displace the 
still but supplement and co-ordinate with it. There is no more con- 
flict or competition than between your thumb and forefinger. The 
field of usefulness of the motion picture or picture movement is dis- 
tinct from the field of the still. Millions love movies. Originally the 
novelty of movement in pictures was sufficient to attract; now merit 
plus movement are essential. 

In the spring of this year I made a survey on the use of the motion 
picture for teaching. While doing this bit of research I visited many 
schools and talked with many school people in different cities. These 
include New York, Newark, Chicago, St. Louis, Cleveland, Kansas 
City, and Pittsburgh. I was in communication with many other 
cities and educators. 

In the following cities the work of visual instruction by means 
of motion pictures is being conducted successfully: Washington, D.C.; 
Meriden, Connecticut; Cleveland, Ohio; Pittsburgh, Pennsylvania; 
St. Louis, Missouri; Kansas City, Missouri; Chicago, Illinois; New- 
ark, New Jersey; New York, New York; Detroit, Michigan. 

The following universities are taking a definite interest in the 
use of the motion picture for teaching, endeavoring to evaluate it and 
to have it function to its best advantage. The Universities of Utah, 
Chicago, Illinois, Indiana, Arkansas, Iowa State College, California, 
Wisconsin, Minnesota, and Texas. 

There is not room in this brief report to present all the facts. 
They lead to three conclusions: 

1. That there is a place for the motion picture in the scheme of 
education in the United States. 

2. That there is a genuine need for such an efficient tool as the 
motion picture under the prevalent practice in American schools. 

3. That there is a demand in the school systems of the country 
for the motion picture as a visual aid to instruction. 

Among the recommendations made are the following: 

The pictures should be essentially those subjects which may be 

visualized best through motion picture action. The field of the still 

picture should be avoided; 

A printed teacher's guide should accompany each reel; 
. Research to evaluate the motion picture for teaching should be 

conducted and the findings be announced publicly and serve as a 

guide to future production; " 

Movies for Teaching — Rogers 69 

There should be an efficient production organization which in- 
cludes on its planning staff both teachers and educators. This organ- 
ization should be capable of expansion and contraction as needs 
require. No large salaries should be paid. Waste in production should 
be eliminated; 

The sales and production organizations should have the guidance 
of people who have sold text books, slides, and other visual aids. 

There should be courses in visual instruction offered to teachers 
to promote a better knowledge of the value of visual aids and greater 
familiarity with motion picture projectors. 

The use of the motion picture holds out three promises : 

1. To teach efficiently, 2. To save time of both pupil and teacher; 
3. To save some cost of teaching. 

Most of the thinking in connection with the motion picture for 
teaching has been along the line of the effectiveness of the movie to 
impart ideas. There are other factors which are of equal and probably 
greater importance. 

With the growing complexity of modern life, with the introduc- 
tion of the radio, the telegraph, the telephone, the aeroplane, the auto- 
mobile, we have invented nothing until the coming of the motion 
picture which will stimulate to quicker thinking, which will enable 
us to impart information with a saving of time and without a loss of 

I attach as exhibit a report of some research which was carried 
on in the schools of New York; New Brunswick, New Jersey, and 
Meriden, Connecticut. I make no generalizations from the report. 
It holds a promise. The gist of the facts is that by the use of motion 
pictures the time for imparting a given amount of information was 
cut in some instances 40 per cent and in others 623^2 per cent without 
a material loss of efficiency. 

The following list of questions was asked a selected well-informed 
group of educators and people interested in visual instruction. Their 
replies are tabulated. Movies are proving their usefulness. 



Function YES NO QUERY 

A. Should motion picture films be correlated with existing 
studies in curriculum? 22 

B. Should they be correlated with textbooks? 19 3 

C. Should they be correlated with other visual aids? 21 

70 Transactions of S.M.P.E., March 1926 


A. Do films promote more efficiency in teaching by helping 

(a) Impart information to the student effectively? 

(b) Arouse the students' attention? 

(c) Hold the students' interest? 

(d) Encourage the students' observation and active effort? 

(e) Stimulate his memory retention? 

(f) Assure a minimum and uniform standard for imparting 

(g) Aid to overcome inefficiency of inferior teachers? 
(h) Stimulate and encourage slow students and reduce 

the number of repeaters? 12 

(i) Stimulate and encourage students with a low intelli- 
gence quotient? 12 

B. Do motion pictures save time by helping to 

(a) Impart, in a limited time, a greater amount of infor- 
mation effectively than oral or printed instruction? 

(b) In what other ways 

C. Do motion pictures save cost by 
(a) Reaching many students simultaneously? 
(b' Reducing "student mortility" or repeaters? 

(c) Reducing truancy? 

(d) Other means 































Frank Benford* 

THE high intensity arc is in many respects so radically different 
from the plain carbon arc that they are nearly as far separated 
as is the carbon arc from the incandescent filament. It is true 
that both are arcs having current passing between spaced electrodes, 
and both have carbon as the current carrier, but here the resemblance 
ends. In the carbon arc the carbon itself is the source of light, while 
in the high intensity arc the carbon is secondary in the production 
of light and acts as a holder for the real source of light which is a small 
body of luminous gas. The current density in the carbon arc is about 
0.33 ampere per square millimeter of crater area, while the current 
density in the high intensity crater is 1.2 amperes per square milli- 
meter. These differences emphasize the fact that the high intensity 
arc is radically different and requires its own mechanism and technic 
for its proper operation. 

This arc is not the first one historically to use a salt-bearing 
electrode for the production of luminous gas, but it is the first one to 
so control the gas that it can be used for projection purposes. The 
flame arc of fifteen years ago had a luminous flame extending between 
electrodes, and this flame being exposed to convection currents, was 
fluctuating in intensity and in constant motion. Also, plain carbons 
have always given some kind of crater on the positive electrode, so 
that two of the basic elements of the high intensity arc, the luminous 
gas and the crater, are individually old in the art of illumination. The 
ingenious feature of the high intensity arc is the combination of a 
luminous gas with a deep crater in which it is momentarily confined 
and thus stabilized in space and in emission of light. 


For the sake of brevity only one size of electrode will be described. 
The 150 ampere arc is the one in most common use and takes a 
16 mm positive and an 11 mm negative. The shells of both are of 

* Physicist, Illuminating Engineering Laboratory, General Electric Company 


72 Transactions of S.M.F.E., March 1926 

extreme hardness. The Brinell tests show them to be as hard as 
mild steel, but being carbon they are brittle and require care in 
handling. The core of the positive is 8 mm diameter, and it is heavily 
impregnated with fluorides of cerium and thorium. These salts will 
be recognized as being the ones used to give the Welsbach mantle its 
selective radiation and under the electrical conditions in the arc they 
are extremely effective light radiators. 

These fluorides are extremely stable and do not change into gas 
except at temperatures near the boiling point of carbon. This is a 
necessary condition, for if salts with a low temperature of vaporiza- 




Fig. 1. — A sectional view of the high intensity arc showing the cores, crater, 
and position of the arc stream and flame. 

tion such as sodium chloride are used they will boil off in a great burst 
of gas and leave the electrode just plain carbon. In addition to a high 
vaporization temperature, the selective radiation of cerium and 
thorium render them excellent light sources, for not only is the zone 
of greatest radiation within the limits of the visible spectrum, but 
the spectrum lines are so numerous as to make the spectrum function 
visually as a continuous spectrum. 

The core of the negative is 3 mm in diameter and is of soft 
carbon. The size of the negative is considerably less than in older 

High Intensity Arc—Benfon 


arc practice, and the carbon gas is given off with a relative high 
velocity. This is a vital feature, for the proper maintenance of the 
arc depends upon the strength and stability of this stream of carbon 


Fig. 2. — Typical craters. 


Fig. 3. — Craters when electrodes are improperly adjusted. 

gas. It has been found that the lamp may be placed on its side or 
inverted, and the negative gas maintains an invariable relation to 
the two electrodes. 


Transactions of S.M.P.E., March 1926 

In speaking of the component parts of the high intensity arc 
the following terminology is usually employed : 

''Arc stream" — The violet stream of carbon gas extending from 
the tip of the negative to within several millimeters of the plane of 
the crater. 

Fig. 4. — ^^A high intensity arc in operation. The white circle was drawn in to 
define the Hmits of useful hght in searchUght practice. 

"Crater gas" — The light-giving gas contained within and adja- 
cent to the crater on the end of the positive electrode. 

"Flame" — The jet of gas formed by the combining of the gas 
streams from the negative and from the crater. 

High Intensity Arc — Ben ford 


The crater gas has by far the highest briniancy. The flame is 
next, being composed in part of the crater gas that escapes over the 
upper rim of the crater, and the arc stream is lowest in intensity, 
being perhaps identical with the arc stream from pure carbon elec- 

A ver}^ necessary condition is the formation of a deep and 
symmetrical crater, and in order to secure this the positive is rotated 
at about sixteen revolutions per minute. The original lamps also 

Fig. 5. — A motor driven studio mechanism for both floodhghting and projection 

rotated the negative, but this was found to be an unnecessary refine- 
ment and is no longer used. 


The proper functioning of the high intensity arc calls for a very 
strict adjustment of the electrodes with respect to one another, and 
when used as the light source in a searchlight the crater must be held 


Transactions of S.M.P.E., March 1926 

A searchlight lamp therefore has the 

accurately at the focal point 
following functions : 

1. Rotation of positive at a constant rate 

2. Feeding of positive to keep crater at focal point 

3. Feeding of negative to maintain constant current 

4. Maintenance of electrodes in accurate alignment 

5. Protection of both electrodes from oxidation by the air 

Fig. 6. — A full automatic lamp for searchlight service. 

The mechanism to carry out these five features is much more 
elaborate than is requu-ed for the plain carbon arc and various lamps 
that are full automatic, semi-automatic, and mechanical feed, and 
manual operation has been developed for different services, but it 
will be appreciated that the high intensity|_mechanism in its simplest 
form" is more elaborate than the low intensitj^ lamp. Item No. .5 

High Intensity Arc — Benford 


above has a long history in the development of the mechanism. The 
original lamps had an alcohol burner under each electrode for several 
inches back from the arc, and the non-oxidizing alcohol flame served 
as a protection against the oxygen of the air. But alcohol introduced 
too much of a complication in military service, and other ways were 
devised to obtain almost the same resistance to oxidation. 

Fig. 7. — A high intensity studio light complete with switches jyid rheostat. 

Adjustment of Electrodes 

The reason for the care taken in adjusting the electrodes of the 
high intensit}^ arc is obvious when we remember that the light source 
is the small volume of gas contained within the crater. The light is 
bright or dim according as the crater is full or empty, and the steadi- 


Transactions of S.M.P.E., March 1926 

ness of the light depends upon the steadiness and freedom from 
turmoil in the luminous gas. 


^ HUM 





^^-4 MM 
^^-5 MM 







Fig. 8. — An analysis of the influence of the position of the negative axis upon 
the output of useful light. 

High Intensity Arc — Ben ford 79 

There are three principal forces acting upon the gas and by 
properly balancing these against one another the arc can be brought 
into control. First there is the stream of carbon gas or arc stream 
given off with high velocity from the negative. Second, there is the 
upward thrust of the magnetic field induced by the current through 
the arc. The third force is the convection forces set up by the 9000 
watts being expended at the arc. 

The luminous crater gas leaves the core with a low velocity, 
and if not interfered with would stream out of the top of the crater 
so that only the upper part would be filled. The arc stream may be 
directed against the upper part of the crater so as to oppose the 
escape of the crater gas, and by delaying its escape the crater is 
kept full to the bottom edge. The current now passes through 
about 8 mm of gas and heats it to a temperature that is apparently 
1500°C higher than is possible with solid carbon. 

The arc stream has a pronounced effect on the form of the crater, 
and considerable experimental work has been done to find the best 
adjustment. As a general rule the deepest crater gives the most light 
but it has been found possible to deepen the crater over its customary 
depth and at the same time decrease the useful light. This condition 
occurs when the negative is adjusted so that its axis intersects the 
plane of the crater several millimeters to one side of the center. This 
is mentioned to illustrate the sensitiveness of the arc to the adjust- 
ment of the electrodes, and to explain why special lamp mechanisms 
are necessary to hold the electrodes properly under the various hard- 
ships that the lamps (the military lamp in particular) must undergo. 

Operating Characteristics 

The most striking feature in the operation of the high intensity 
arc is its continuity. Not that the arc does not break, but when an 
outage does occur the pick up is almost instantaneous, and a rupture 
of the arc usually means nothing more than a momentary drop in 
illumination. Upon starting a fresh trim of electrodes several seconds 
are consumed in bringing the positive up to approximate final temper- 
atures and to develop a crater of sufficient size to collect crater gas. 
But once in operation, a break in the arc results in a drop of intensity 
only during the period that it takes the negative electrode to come 
up to the plane of the crater. It is not necessary for the hot carbons to 
touch because the crater gas is a good conductor when hot, and the 
arc will jump across ten millimeters of hot gas. In the type of mech- 


Transactions of S.M.P.E., March 1926 

anism where the negative head is actuated by a spring, the time 
during which the arc is out is therefore but a small fraction of a 





-17. G8 
















' ct 





O £ 4 G 


Fig. 9. — Relation between screen illumination and height of negative electrode- 

second,' but if the negative must be fed forward, then several seconds 
may elapse, and if the feed is too slow it may be necessary for the 
negative to enter the crater and establish carbon contact. 

High Intensity Arc — Benford 


The second feature of the arc is its relative steadiness of opera- 
tion. There is a flicker of small amplitude that is continuous, but this 
flicker is largely in the gas that spills over the sides of the crater. 



VOLTS /^RC. 73 
WATTS 16000 

J / / / "W-o'*SZ\5^'^ 







\ \X \-sV^t~~/ // / 



























\. /\^ /"^-^ 7 



Fig. 10. — An analysis in one plane of the bare arc into total light, crater 
light, and light coming from within a fixed radius of the center of the crater. 


Transactions of S.M.P.E., March 1926 

It gives the searchlight beam a noticeable flicker around the edges, 
but in motion picture work this flicker is largely overcome by the 








TOTAL RAD/ATJOn(0-63.5VLUMEn5 //^fS l 

USEFUL FAD/ATIOL/(0'"-G3.SyLUMEn 3 ^^^^^^ 





Fig. 11. — An analysis in all planes to show total light and light useful for search- 
light projection. 

•optical arrangement, particularly at the aperture, that reduces 
fringe light to a minimum. 

High Intensity A)'c — Benford 


A third, and a most valuable feature, is the permanence of 
position of the light. In motion picture projection the active area of 
the plain carbon arc is much larger than required at any particular 
moment so that the movements of the crater will not take it out of 
focal position. The high intensity arc is fixed in position, and the 
crater forms a light source of invariable size and position. 


^ r\i -^ s^ Qq ^ 
O O c^ Ci ^ S 






























1 \ / 
















































Fig. 12. — The upper line shows the relation between Hght and current when 
the various electrodes are operated at their rated current. The lower hne shows 
the decrease of hght when the same electrode is operated at reduced current. 

Photometry of Bare Arc 

There are several peculiar features about the generation of light 
that make the photometry of this arc of peculiar interest. It is a rule, 
although not a universal one, that light not originating in the imme- 
diate neighborhood of the focus is wasted so far as projection is 


Transactions of S.M.P.E., March 1926 

concerned. Therefore, in the photometry of the high intensity arc 
it is necessary to separate out the hght that comes from the flame 
which extends six to eight inches above the crater. The lower part 
of this flame, being composed of crater gas, is highly luminous, and 
the whole flame and arc stream contains some 37 per cent of the 
total output. In the development of these electrodes it was necessary 
to constantly determine the percentage of waste light, for in man}^ 
cases an electrode would have a greatly enlarged flame with no 
equivalent gain in useful light. 











J. -^ 




^ / 



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— 1 





;— ^ 









v ' 







, "^N, 












'\ ^ 

^ -^ 


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ibL ^ 



~ Crj 






7 / 2 3^ 3 c^ -7 9 ^ 


Fig. 13. — An analysis of the brilliancy of the arc made so that all useful hght is 


It has been the practice to project an image of the bare arc 
upon a screen and have in this screen an opening of proper size and 
shape, so that only the useful light can pass through into the photo- 
meter. For equal currents the useful projection light exceeds that of 
plain carbon by nearly 90 per cent, and for floodlighting where all 
light is useful the excess amounts to about 250 per cent. 

Intrinsic Brilliancy 

In practically all projection work the intrinsic brillianc}^ of thb 
light ^source is the criterion of its usefulness, and judged by this 

High Intefisity Arc — Benford 85 

standard the high intensity arc is without a peer and almost without 
a competitor. The brilhancy in the center of the crater, where the 
gas is deepest, is 850 candles per sq. mm, as against 135 candles per 
sq. mm for plain carbon and 35 candles per sq. mm for a tungsten 
filament. It is thus by far the most intense source of Kght available, 
and in those cases where brilliancy is of first importance this arc is 

Measurements show the brillianc}^ of am^ particular area of the 
crater to be almost directly proportional to the depth of gas at the 
point under observation, with a practically constant addition due to 
the surface of the crater. This indicates a brightness of over 715 
candles per square millimeter due to the boiling carbon. 

Color Analysis 

If we judge the temperature of the gas by its color, we find a color 
temperature of 5400° Absolute, or about the same as the color tem- 
perature of the sun after it has been filtered by the earth's atmosphere. 
The high intensity spectrum is composed of a weak background 
due to the carbon walls of the crater overlaid with a large number 
of bright lines due to the core salts and to the combinations formed 
between these salts and the carbon. It has also been surmised that 
the nitrogen of the air unites with the other components to form 
cyanogen and other elusive compounds that form at the high tem- 
peratures found in the crater. The number of lines distinguishable 
in the visible spectrum with a low power spectroscope runs into the 
hundreds, and there is no region that may be said to form a dark 
space. For purposes of illumination the spectrum is therefore con- 
tinuous. The onh^ region that might be taken as an exception to this 
is in the violet region, where the lines from the carbon gas give a 
pronounced peak. The projected beam, be it either searchlight or 
motion picture projector, does not ordinarily show any strong excess 
of violet because this light is strongly absorbed b}^ the glass in the 
optical system, and the resultant spectrum takes on the general char- 
acteristic of bright sunlight, with a small excess of energy in the 
blue and \dolet region. 

Some years ago comparative tests were made to determine the 
camera speed of projected beams from plain carbon, high intensity 
arc, and from unreflected light from Cooper-Hewitt arcs with glass 
tubes. The basis of comparison was equal illumination on the plane 
of test. The speeds found were one, five, and five in the order used 

86 Transactions of S.M.P.E., March 1926 

above, and with unreflected light the ratio figure for the two arcs 
would have been considerably higher. 

Fig. 14. — The continuous spectrum is from boiling carbon, and the spectrum lines 
are from carbon gas and possibly cyanogen. 

Fig. 15. — The multiplicit}' of lines from the high intensity gas almost completely 
obscures the continuous spectrum of the carbon crater walls. 

High Intensity Arc — Benford 




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^OAOJJ 0.45 

0.50 0.55 O.Ol 

0.Q5 0.70 


Fig. 16. — A typical spectrum analysis curve of the useful light of the bare arc. 


Transactims of S.M.P.E., March 1926 






: r r T" i: 

t i ^ il 

Y " ■"+ 

Lit -^- 4 

V t 1 I -+ -■ 

^ t i t V- 4 

^11- -+ ^ 

^ V \- X- 

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t ^^. I 


M^--^'— 5^3- ^■-^y^_-^?__..^-/^__^ 

0.40 U 0.45 0.50 0.55 O.GO 0.65 0.70 U 

Fig. 17. — A spectrum analysis of the flame immediately above the crater. The 
great excess of violet is from the carbon gas of the arc stream. 

High Intensity Arc — Benford 


1 10 










a 10 












■ — 


— ■ — ■ 














11 u 














A /■ 







^-1 ' 


, ^ 




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O.mZO 40 60 dOO.500 ^0 40 60 800.60020 40 GO 60 0.700 20 4€ 

Fig. 18. — A spectrophotometric comparison of useful light from plain 
carbon and high intensity arcs. This analysis shows the influence of mirrors or 
lenses in absorbing the excess of violet. 


Mr. Griffin: Will you outline for us what you have found with 
regard to the speed of rotation of the high intensity arc positive 
carbon? I ask this because we have taken over from the General 
Electric Company the manufacture of the high intensity arc for 
motion picture work; that is, the model they have formerly sold, 
and while we could formerly send all the complaints to the General 
Electric Company, we must stand on our own feet now. Some 
persons claim that if the speed is reduced to one-half that now used, 
much finer results are obtained. Our tests do not indicate that it is 
so serious, but the particular reason I have in mind for asking is that 
one of the lamps put out recently uses a lower speed of rotation. 

Mr. Palmer: What is the proper arc voltage in a 150-ampere 
lamp, and can we be sure that we are operating the lamp at its highest 
efficiency if we hold the arc voltage at that amount? 

Mr. Richardson: The principal objection to the high intensity 
arc has always been its harsh tone. May I ask what progress has 
been made, or what, if anything, has been accomplished in reducing 

90 Transactions of S.M.P.E., March 1926 

the harshness of the Ught? Another objection to the high intensity 
and to the ordinary arc is condenser pitting and breakage. I have 
thought it was possible to air cool the condenser by a blast of air 
over the condenser lens, and I have brought the matter to the atten- 
tion of the Nicholas Power Company and suggested that tests be 
made. I also have often wondered if it were not entirely possible to 
eliminate all fire hazard by a blast of air in front of the film. 

Dr. Hickman: What constitutes a high intensity arc? If one 
takes an ordinary, plain carbon arc and increases the current four 
of five times, the crater area spreads four or five times without altering 
the intrinsic brilliancy. What is the mysterious thing in the high 
intensity arc which makes the four amperes sit contentedly in the 
space occupied by one before? 

Then, I notice that cerium chloride and the rare earth fluorides 
were mentioned as being the light source. A spectrum photograph 
shows a gaseous emission and not the ordinary black body radiation. 
In incandescent mantle manufacture they are selected because of the 
emission in the solid state. I should like to know why they are chosen 
in gaseous emission. When the cerium fluoride volatilizes in air at 
high temperatures, the fluorine is driven off, and the brown oxides 
tumble down. Carbons are consumed at the rate of 10 inches an 
hour. The fluorine from this must act on the operator at some time 
or other. 

What is the effect of increasing the voltage across the gap to 
allow a greater flux of light. 

I should like to say to Mr. Richardson that when I was in Ham- 
burg I saw a means of cooling the gate with a blast of air on it and 
know that it was very satisfactory. 

Mr. Little: The curves would appear sufficiently close to 
black body radiation characteristics in order to express them in 
terms of approximate color temperature. Could Mr. Benford so 
express them in the manuscript before it is sent to the publisher? 

Mr. Stark: Answering Mr. Richardson's question, in motion 
picture projection it is possible to overcome the harsh ''high inten- 
sity" tone by the use of suitable filters. As a matter of fact, it is 
becoming an almost universal practice to tint positive film — usually 
yellow or amber — so that the blue light of the high intensity carbon 
arc is appreciably cut down to a semblance of white light. 

Another method, more precise and more efficient, was presented 
to the Society by Dr. Kellner at the Ottawa meeting of 1923, in a 

High Intensity Arc — Benford 91 

paper entitled "Can the Efficiency of the present Condensing System 
be Increased?" 

I should like to ask Mr. Benford why it was necessary in the 
original Beck high intensity arc lamp to "cool" the positive carbon 
by "heating" it in an alcohol flame; and why it is no longer necessary 
to do this in the present type of lamp? 

Dr. Sheppard: Has Mr. Benford any data on the absolute 
amount of ultra-violet energy between 3000 and 3500 with the lens 
in position? 

Mr. Powrie: What is the object in using a third electrode of 
copper in a high intensity arc? 

Mr. Bexford: Regarding the speed of the 150 ampere positive 
carbon, the speed of rotation was set at 16 revolutions per minute, 
and we never found that the light was very much influenced by 
changes of two or three revolutions a minute either way. I believe 
the 75-ampere arc runs at twelve revolutions a minute, and I must 
confess that I do not believe the quantity of light will be greatly 
changed by lowering the speed to, say, eight revolutions a minute. 

In regard to the proper voltage of the 150 ampere arc, it is 
usually set between 75 and 80 volts at the arc. You may increase 
this and run the voltage up to 85 or 90, in which case there will be 
a small increase of light, but the arc becomes unstable. You can gain 
light and lose in stability, and it is an engineering choice as to where 
to stop, and the General Electric engineers think 75 to 80 volts is 
the best all around voltage. 

Mr. Palmer: In maintaining the arc voltage, is a sufficient 
accuracy maintained or would j^ou have to measure the amperage? 

Mr. Bexford: The automatic lamps are built to maintain 
current by means of changing the arc length. If you change the 
line rheostat the arc changes length. We selected this because the 
light is more sensitive to current than voltage, and we thought this 
would give the most uniform condition of light. 

Mr. Richardson asked about contemplated changes in color. 
We have not done anything on this, and I don't think anything is 
under consideration. We feel that the most light is the best, and if 
the tone is not right, we can correct it by means of filters. 

Mr. Richardsox: Do j^ou mean that it would be impossible to 
change the tone without decreasing the illumination value? 

Mr. Bexford: Almost that; we cannot be quite certain, but 
we have searched for the most light. 

92 Transactions of S.M.P.E., March 1926 

We have tried putting a blast of air over condensers, and as 
far as the arc is concerned it doesn't matter as long as air doesn't 
reach the arc; that would be serious. 

With regard to the increase of current four times: If you do 
this, with plain carbons the crater area increases; the high intensity 
electrode is much harder than the ordinary and is a better conductor. 
Also, the gas given off by the core is a very good conductor, and it 
tends to concentrate the current in the center of the arc rather than 
allow it to spread around the edges of the electrode, ^^'^len I started 
work on this arc I was warned to watch out for poisonous gases. 
It was suspected there would be harmful gases in the air which would 
attack the mirror, but in my experience I have never seen any direct 
evidence of the operator or the apparatus being attacked by the 
fumes. I have worked a number of times under extremely unfavorable 
conditions in a closed room which smoked up badly, and I have 
never suffered any ill effects, and I have never seen a mirror that was 

I believe Dr. Hickman also asked about increasing the arc 
length and I can answer that by saying that the arc becomes unstable 
if stretched too far. 

With regard to labeling the curves with color temperature, this 
is pretty much of a guess. It is merely a convenience in speaking 
of the thing to say that it looks like black body radiation. 

In answer to Mr. Stark, it is a fact when Mr. Beck first developed 
the electrodes that he could not get carbons of sufficiently high 
density to withstand the current density and his electrodes oxidized 
rapidly, so he surrounded the electrodes with a non-oxidizing alcohol 
flame. That apparently would add to the temperature but did not; 
the electrodes run cooler with the alcohol flame than without. If you 
exclude the air you eliminate the outside burning, which is a source of 
heat; with the alcohol flame the current density is not so high on 
account of the greater cross section of electrode, and there is less 
resistance drop in the electrode itself. After we took up the production 
of these lamps, the Army and Navy objected to the use of alcohol 
as being too fussy, and the tank had a habit of leaking, so that a new 
electrode was developed to resist oxidation better, and we found it 
possible to crowd the heads up towards the arc so that the oxidized 
length was not so great, and the use of alcohol was not so important. 
. A third electrode has been used to control the focal position. 
If the crater burns back with a third electrode, some current is 

High In ten sity A re — Benford 93 

carried off from the tip of the flame to operate the feeding mechanism. 
We don't use that method; we have used an optical s^^stem of throw- 
ing the optical image on the thermostat mechanism. 

I have never measured the energy between 0.290// and 0.330/i. 
The camera speed of the high intensity arc is about five times as 
great as plain carbon, so that the energy in that region is probably 
in the neighborhood of five times as great. 

Mr. Griffijvt: While it is irrelevant to the discussion of the 
high intensity arc, with regard to the air blast, I think if Mr. Richard- 
son will go back three or four Transactions, he will find that I built 
an apparatus in which the air blast was used satisfactorily in the 
aperture of the projector. This was developed by Targets, Limited, 
London, fifteen or sixteen years ago. 

Mr. Kunzman: Has your laboratory analyzed the gases referred 
to in the high intensity arc? 

Dr. Hickman: Why was cerium chosen rather than anything 

Mr. Hubbard: What is the total beam candle power of the 
150 ampere lamp using a 24'' mirror compared with the 60" mirror? 

Dr. Sheppard: What degree of constancy is obtained actually, 
and how constant could it be made with some refinement? I should 
like to know this because of the possibility of using the lamps in 
photo-chemical work. 

Mr. Benford: I have never heard of an analysis being made of 
the gas. 

With regard to the constancy, the arc is much more constant 
in its output than plain carbon; there is a flicker of 5 per cent going 
on, a fluctuation of short duration, but over long periods it is very 
constant because the current is constant, so that from hour to hour 
it is more constant than plain carbon. 

The particular chemicals used in the carbons were chosen for 
the same reason that they were chosen for the Welsbach mantle. 
They were available to Mr. Beck when he started the job, and we 
have never found anj^thing better. 

About the candle power: We get into big figures. I have never 
tried this with a 24" mirror because we never had a mirror which 
would stand such an arc. It should give about 150,000,000 candles. 
The 60" mirror with a 150 ampere arc at the present time will test 
up to 725,000,000 candles, and it is theoretically possible to boost 

94 ~ Transactions of S.M.P.E., March 1926 

this over a billion, and work is being done at the present time on the 
re-design of the mirror. 

Mr. Ziebarth: We are using air for cooling the film in our 
Filmo projectors, which enables us to stop the machine and show 
still pictures. A description of this may be found in our 1924 Trans- 
actions in a paper by J. H. McNabb. 

Mr. Richardson: That is true, but so far no attempt has been 
made to lessen the fire hazard with the high intensity or the reflector 
type lamps. 

Dr. Hickman: This method of cooling film with a blast of air 
has been patented and cross-patented any number of times in the 
last four or five years. I have seen many different modifications 
none of the patent claims of which are valid, and there are a number 
of continental machines fitted with the devices. All the various 
patents are chronicled in the Kodak Abstract Bulletin or the R.P.S. 
"Photographic Abstracts," and I make a plea for a subscription to 
some such abstract journal by everybody connected with the indus- 
try, since it would save cross-patenting and cross-designing of 
what other people have done. 

Mr. Griffin: This explains very well why the manufacturers 
do not go into this. No one is looking for lawsuits, and the apparatus 
as used today is quite satisfactory. The building of compressed air 
apparatus is costly and takes up room in the projection room; it is 
subject to breakdown. I think it will be a long time before the 
manufacturers adopt such an apparatus. 

Mr. Richardson: I don't believe any costly apparatus is 
necessary. I think the thing could be taken care of bj^ a high speed 
electric fan with a proper air shoot. The reason I brought this up is 
that we have been using high power light sources and very hot spots 
in the last year or two. 


J. I. Crabtree and C. E. Ives 

WHEN developing motion picture film by the rack and tank 
system it is very difficult to secure uniform development 
throughout the entire length of the film. Unless special precautions 
are taken, more development occurs at the top and bottom of the 
rack where the film passes over the end slats or bars than along the 
sides, so that bands of greater density occur at intervals correspond- 
ing with the height of the rack, which cause an objectionable flicker 
when the film is projected. These dark markings are termed "rack 

Another difficulty arises from the clinging of airbells to the film 
as the rack is immersed in the developer. These airbells prevent the 
access of developer to the film locally thus causing white spots. 

Both the above defects can be overcome by correct manipulation, 
but their presence on much of the film shown in the present day 
theatre indicates a need for a better knowledge of the subject on the 
part of many laboratory workers. 

It is the purpose of this article to explain the nature and cause 
of rack marks and airbell markings on motion picture film and to 
indicate methods for their prevention. 

Rack Marks 

When film is developed on the usual rack in a vertical tank, more 
development invariably occurs where the film passes over the top and 
bottom of the rack than along the sides, causing the film to appear as 
shown in Fig. 1. The marking where the film passes over the top of 
the rack is usually mottled and consists of a double line, while at the 
bottom only a single dark line is produced. 

Cause of Rack Marks. — At various times rack marks have been 
wrongly attributed to causes such as a difference in temperature 
between the rack slats and the developer, which might cause an ac- 

* Communication Xo. 250 from the Research Laboratory of the Eastman 
Kodak Company. 


96 Transactions of S.M.P.E., March 1926 

celeration or retardation of development at the point of contact of 
the film with the slat. Experiments have shown, however, that more 
development occurs where the film passes over the slats even when 
the rack is cooled below the temperature of the developer before im- 
mersion. It is now known that rack marks are caused by non-uniform 
development due to convection currents and retardation of develop- 
ment of the film along the sides of the rack by the developer exhaus- 
tion products. 





Fig. 1. Typical Development Rack Marks on Motion Picture Film 

In order to demonstrate the non-uniformity of development at 
the top and bottom of the rack a length of motion picture film was 
given a uniform exposure and developed for the normal time, five 
minutes, at 65° F., the rack being kept stationary. The density of 
the developed film was measured in several places at the top, middle, 
and bottom of the rack and the average measurements were found to 
be as follows: 

Top of Rack Middle of Rack Bottom of Rack 

' 1.32 1.15 1.02 

Rack Marks and Airhell Markings — Crabtree and Ives 97 

This grading of density from top to bottom of the rack is due 
to the fact that wherever development occurs reaction products con- 
sisting of oxidized developer and sodium bromide are formed. These 
substances are strong restrainers of development and have a greater 
density or specific gravity than the fresh developer and therefore tend 
to flow downward, while developer flows from above to take its place. 
As the developer flows down the vertical film it becomes gradually 
more and more exhausted because it has assisted in developing the 
upper portions. This results in a gradual diminution in the degree of 
development of the film from top to bottom of the rack. 

The actual existence of convection currents in a vertical develop- 
ing tank has been shown by Bullock/ who placed paper fibres in the 

WiTTiO ^^^ 

^ m ♦ ^ m • 


# ♦ • 


Fig. 2. Streaks caused by the Restraining Action of the Products of Development 

solution. During development the fibres were observed to travel 
downwards along the film and then upwards at the side of the tank. 

The restraining effect of the reaction products of development 
may be very clearly demonstrated by exposing a strip of film through 
a metal plate punched with a number of holes, slightly flashing the 
whole film to light and then placing the film vertically in the de- 
veloper without agitation. Immediately below each black circle 
which develops up, a white tail is produced as shown in Fig. 2 caused 

1 "On the Convention Effects in Photographic Bathing Operations in the 
Absence of Agitation," by E. R. Bullock, B J. Phot., Feb. 1922, p. 110. 


Transactions of S.M.P.E., March 1926 

by the restraining effect of the reaction products from the develop- 
ment of the circles, which reaction products gravitate downwards. 
If the film is wetted before being placed in the developer the white 
tails appear above the circles (Fig. 2) because the reaction products 
diluted with the water absorbed by the film have a lower specific 
gravit}^ than the developer and, therefore, travel upwards. 

The probable direction of the convection currents occurring in a 
vertical motion picture developer tank is shown in Fig. 3. 

The main currents ABFE and CDHG flow parallel with each 
side of the rack. At the bottom of the rack small eddy currents 

Fig. 3. Diagram Illistrating the Probable Direction of the Convection Currents 
in a ]\Iotion Picture Developing Tank 

probably exist, while across the top of the rack the developer remains 
relatively stationary. 

At the points B and C the developer is continually renewed, 
while between these points the reaction products of the developer 
remain stationary and development is restrained so that a double 
rack mark is produced as shown in Fig. lA . At the points F and G, 
development is restrained by the reaction products flowing down the 
film, while between these points the developer is being continuously 

Rack Marks and Airhell Markings — Crabtree and Ives 99 

renewed by virtue of the eddy currents, so that only a single rack 
mark results as shown in Fig. IB. 

Negative rack marks appear as light bands on the positive print. 
The positive film may therefore contain both negative (light bands) 
and positive (dark bands) rack marks at varying intervals but sepa- 
rated by a distance not greater than the height of the rack. Only in 
rare instances do the positive and negative rack markings coincide. 

Methods of Preventing Rack Marks.— -Since rack marks are caused 
by non-uniform development, the remedy is somewhat obvious, but 
it is very difficult in tank work to ensure that each portion of the film 
develops at exactly the same rate. To attain this end the developer 
must be renewed at each point at the same rate, and this can be 
partly effected in the following ways: 

1 . By agitation of the developer with the rack remaining stationary. 
This can be accomplished by means of a pump or mechanical stirrer, 
but in the case of a deep tank it is almost impossible to so agitate the 
developer that the rate of renewal of the developer at the surface of 
the film is constant throughout its entire length. The experiment was 
tried of injecting a stream of nitrogen gas (so as not to oxidize the 
developer) at the bottom of the tank, but unless an even stream of the 
gas passed up each side of the rack uneven development resulted. In 
view of the expense involved and the difficulty of securing uniform 
agitation, this method was abandoned. 

2. By agitation of the rack. The rack can be agitated in the 
following waj^s: 

(a) By lifting the rack vertically out of the developer and re- 
immersing. This is the only method of agitation possible if the tank 
is fitted with rack guides. The rack is normally held down under the 
solution by a suitable fastener but on releasing this, the rack tends 
to float and usually protrudes about halfway out of the tank. If the 
rack is again submerged this will produce sufficient agitation to re- 
place the reaction products of development at the surface of the film 
with fresh developer and mix the developer as a whole so as to be more 
nearly homogeneous. 

The question arises as to how often agitation is necessary. The 
process of lifting and re-immersing the rack in a vertical direction 
causes a strong current of developer to strike against the lower slat, 
which tends to produce more development at that point and accen- 
tuate the rack marks. Experience has shown that agitation of the 
rack by allowing it to rise out of the developer and immediately re- 

100 Transactions of S.M.P.E., March 1926 

immersing: once every minute produces an effective degree of agitation 
of the developer. 

(b) By leaving the rack fully immersed and imparting to it a 
"square motion"; that is, the rack is moved horizontally across the 
tank away from the operator, then vertically downwards, then across 
the tank towards the operator, and then vertically upwards. This 
manipulation may be termed the "square motion" and is only possible 
if the tank does not contain rack guides and if the depth of the liquid 
is somewhat greater than the height of the rack. Experience has 
shown that the rack must be agitated almost continuously in this 
manner in order to produce effective agitation, but this is not practi- 
cal, and in case the film is developed by time it is difficult to duplicate 
the degree of agitation. 

3. By moving the film along the rack during development. This can 
be effected in two ways: 

(a) By winding the film on a roller rack previously described ,2 
which consists essentially of a regulation rack with the end slats 
replaced by rollers. By attaching the film at each end to the rollers 
by means of rubber bands and turning the upper roller during de- 
velopment, the film is progressed along the rack spirally, and any 
unevenness of development at the roller end is distributed over the 
film for a length of two or three feet, and rack marks are therefore 
effectively prevented. When using such a rack it is desirable to 
agitate the developer by lifting the rack out and re-immersing once 
every two minutes. Owing to its relatively higher cost and the extra 
time required to load such a rack, it has not been generally adopted, 
though as a means of preventing rack marks it is highly effective. 

(b) By progressing the film along the rack manually. This is 
accomplished by attaching the film at each end by means of a long 
rubber band capable of being stretched two or three feet. The same 
procedure is then followed as when tightening the film after winding 
on the rack, although this is carried out while the rack is completely 
immersed under the developer. By advancing the film spirally in 
this way every two minutes fairly even development is obtained. 

This procedure requires the undivided attention of the operator 
and is otherwise objectionable but is the only alternative manipula- 
tion to the roller rack method for completely eliminating rack marks. 

2 'iThe Development of Motion Picture Film by the Reel and Tank Systems," 
by J. I. Crabtree, Trans. S.M.P.E., Vol. 16, p. 163. 

Rack Marks and Airhell Markings — Crabtree and Ives 101 

4. By making the end slats of the rack as broad as possible and with 
a curved surface. This has the double effect of producing better stirring 
of the developer on agitation of the rack and of broadening out the 
rack marks. Experience has shown that a broad rack mark which 
grades off gradually at each side is less objectionable on projection 
than an extremely narrow one produced by a V-shaped end slat. It 
has been found that cylindrical end slats having a diameter of about 
two inches as shown in Fig. 4 are the most satisfactory and practical. 

The following experiment was also tried. Strips of wood two 
inches wide were attached by means of clips across each end of the 
regulation narrow slat rack to provide an efficient means of stirring 

Fig. 4. Film Developing Rack with Offset Spacing Pins 

and to protect the ends of the rack from an excessive flow of developer 
when the rack was agitated. Though moderately effective in dimin- 
ishing the intensity of the rack marks, better results were obtained 
with the cylindrical slats. 

5. By developing as far as possible to completion. As explained 
above, since rack marks are produced by virtue of one portion of the 
film receiving more development than another, it follows that the 
propensity for rack marks to be produced is greater when the film is 
developed to a low degree of contrast than when the limiting contrast 
is attained. In other words, with a fully exposed positive, printed 

102 Tronsadions of S.M.P.E., March 1926 

from a contrasty negative, which must be developed in a weak de- 
veloper for a short time, there will be a greater propensity for rack 
marks to be produced than in the case of a print from a flat negative 
which must be developed to the limit. The matter of the degree of 
development of any rack of film is, of course, determined by the re- 
quirements of photographic quality. Special care, however, must be 
taken when developing to a low degree of contrast. 

Practical Instructions for Preventing Rack Marks 

By employing racks with cylindrical slats of approximately two 
inches in diameter as shown in Fig. 4, allowing the rack to emerge 
from the developer and immediately re-immersing once every minute 
during the course of development, both negative and positive rack 
marks are so effectually eliminated as to be practically invisible on 
the screen. 

For precision work, when more absolute uniformity of develop- 
ment is desired, either the roller rack should be employed and the 
rack agitated once every minute, or the film should be progressed 
along the rack manually as explained above. 

It should also be remembered that full development of the posi- 
tive or negative tends to eliminate rack marks, and although the 
degree of development is determined by the requirements of photo- 
graphic quality, it is desirable not to over-develop the negative in 
order to eliminate the necessity for giving an extremely short develop- 
ment of the positive, which is necessary with a contrasty negative. 

Fixing Bath Rack Marks 

Rack marks may be produced independently in the fixing bath 
if the rack is not agitated, especially during the first few minutes of 
fixation. Owing to the fact that the film is saturated with developer 
when immersed in the fixing bath, the film continues to be developed, 
especially in a fixing bath which is weakly acid, until all the alkali 
in the developer is neutralized by the acid in the fixing bath. If the 
rack is not agitated, the rate of neutralization of the developer takes 
place more slowly at the top and bottom of the rack because of verti- 
cal convection currents along the sides of the rack as outlined above 
under "development," so that the film continues to develop locally, 
causing rack marks. To prevent this, the rack should be agitated 
several times on first immersing in the fixing bath so as to ensure 

Rack Marks and Airhell Markings — Crahtree and Ives 103 

complete neutralization of the alkali in the developer, thus arresting 

Toning Rack Marks 

When toning film on a rack in a single solution tonier such as 
a uranium or iron toning bath, it is extremely difficult to obtain 
uniform toning especially if only a weak tone is desired. In the 
case of sulphide toning, when the bleaching and sulphiding processes 
are carried to completion no difficulty is encountered, but with the 
above toning solutions toning is progressive with time and for the 
same reason as outlined under development, there is less tendency 
for rack marks to form the nearer the degree of toning is carried to 
completion. Any rack mark already present due to development 
will also be intensified in toning and unless guarded against, new 
rack marks will be produced during toning. It has been found that 
the procedure of raising the rack out of the solution every minute is 
not sufficient to prevent toning rack marks. In addition, it is neces- 
sary either to use a roller rack or progress the film along the rack 
manually. The following procedure is recommended: 

a. Use a roller rack or one with two inch cylindrical slats as for 

b. Attach the ends of the film by means of rubber bands suffi- 
ciently long to give and take through a distance equal to about three- 
fourths of the rack height. 

c. After immersion, stretch the band at one end and feed the 
film back spirally from the other end in steps of four to six inches 
every two minutes in a manner as outlined under development. 

Even with the above procedure, slight toning for a short time 
is not possible. Toning should be carried out for at least one quarter 
of the time required for toning to the limit. 

In view of the fact that both the uranium and iron toned images 
are partly soluble in alkali, if the water is at all alkaline, uneven 
washing may cause local reduction of the toned image, which results 
in unevenness. This may be prevented either by progressing 'the 
film along the rack during washing or by washing by means of succes- 
sive soakings in water weakly acidified with acetic acid. 

When developing on a reel, bar marks or slat marks are invariably 
produced at or near the point where the film passes over the slat or 
bar. This is because the slats act as paddles to agitate the developer, 
and the impact of the developer against the film is greatest at or near 

104 Transactions of S.M.P.E., March 1926 

the slats, so that the developer is renewed most rapidly at these 
points, resulting in an increased rate of development. 

Curved markings, as shown clearly in Fig. 5, are also produced as 
a result of curling of the film between the bars, which causes the 
developer to flow more or less in specific channels. 

Reel bar marks may be minimized by using a reel with as many 
slats as possible so that the cross section approximates to a circle, by 
avoiding rapid rotation of the reel, and by reversing the direction of 
rotation of the reel at intervals. 

Airhell Markings 

When a strip of motion picture film is immersed in a developer 
or other solution, there is always a tendency for more or less air to 
be carried along with the film under the solution, where it immediately 
tends to assume a spherical shape resulting in a so-called airbell, see 

Fig, 5. Bar Markings Produced when Developing Film on a Reel 

Fig. 6. The bubble of air usually clings to the film throughout the 
course of development unless for some reason it is dislodged, and it 
prevents access of the developer so that on subsequent fixation a clear 
spot or airbell marking remains. Sometimes the airbell persists 
throughout fixation or is formed again on immersion of the film in the 
fixing bath, so that after washing a spot of unfixed-out emulsion 

Clear airbell markings produced on negative film appear as dark 
spots on the positive, and in view of the present practice of developing 
negative film on racks and positive film on processing machines, which 
do not have so great a tendency to give airbells, most airbell markings 
seen on the screen at the present time are dark spots caused by air- 
bells on the negative. 

Rack Marks and Airhell Markings — Crahtree and Ives 105 

At the moment of formation the airbell is usually hemispherical 
and has a relatively large area of contact with the film, but owing to 
the tendency of the airbell to assume a spherical shape the area of 
contact with the film tends to become very much smaller. As the 
area of the circle of contact diminishes due to this change in shape, 
the emulsion previously protected becomes partially developed, 
which results in a clear spot corresponding in size to the area of con- 
tact of the final airbell, surrounded by a dark ring of lighter density 
than the surrounding area. 

Fig. 6. Air Bubbles Clinging to Motion Picture Film 

If the airbell forms on the film along the sides of the rack, owing 
to the tendency of the air to rise to the surface, the airbell frequently 
becomes elongated so that the area of contact is not circular but oval. 
The tendency for distortion is greater with the larger airbells, which 
explains why the larger airbell markings are rarely circular, while the 
small markings are invariably circular. A typical group of circular 
and irregular airbell markings is shown in Fig. 7. 

Unless the surface of the emulsion is locally greasy or burnished, 
the points of attachment of the airbells are determined merely by 
chance. However, there is usually a greater propensity for the air- 


Transactions of S.M.P.E., March 1926 

bells to become attached where the film passes over the ends of the 
rack, so that rack marks are usually accompanied by airbell markings 

(see Fig. 8). 

Fig. 7. Group of Circular and Irregular 
Shaped Airbell Markings 

Fig. 8. Airbell Markings Coincident 
with a Rack Mark 

Fig. 9. Airbell Marking — Clear Spot 
Surrounded by a Dark Ring 

P'iG. 10. Airbell Marking — Clear Spot 
Surrounded by a Dark Ring Accom- 
panied by a Tail 

Classification of Airhell Markings 

Airbell markings may be of the following types : 
1 . Clear white spots. These may be either circular or irregular in 
shape, as explained above. (See Fig. 7). The clear cut edges of the 

Rack Marks and A irbell Markings — Crahtree and Ives 107 

spots indicate that the area of contact of the airbells did not mater- 
ially alter during the course of development. 

^. Gray spots. These are similar in shape to those illustrated in 
Fig. 5 but are not perfectly clear and contain more or less silver grains. 
They are caused by the airbell breaking or becoming dislodged during 
development so that the spot was protected for only a part of the 
total time of development. 

3. Clear spots surrounded by a dark ring, (see Fig. 9). The dark 
ring is probably a result of developer oxidation fog caused by local 
oxidation of the developer by the airbell. This type of marking occurs 
only rarely and with freshly mixed developers which are susceptible 

Fig. 11. Airbell Marking— Clear Spot 
Surrounded by a Gray Ring 

Fig. 12. Airbell Marking— Clear Spot 
with Central Dark Ring 

to aerial oxidation fog. In such a case if the film remains stationary 
during development the oxidation products of the developer flow 
down the film and frequently produce a fog streak or tail as shown in 
Fig. 10. 

4. Clear spots surrounded hy a gray ring, (see Fig. 11). The gray 
ring is probably caused by a diminution in the area of contact of the 
airbell with the film due to a change in shape during development as 
explained above. 

5. Clear spots with a dark central ring, (see Fig. 12) . Examination 
of the dark nuclear ring showed that this consisted largely of silver. 
The exact method of formation of such markings is not known, though 
they could be formed by bursting of the airbell just before the film 

108 Transactions of S.M.P.E., March 1926 

was removed from the developer so that the whole airbell area became 
saturated with developer, and the reforming of a smaller central 
bubble when the film was immersed in the fixing bath. This second 
bubble would prevent the access of the fixing bath and permit of 
development of the image underneath by the developer absorbed by 
the film after the bursting of the first bubble. 

Such a marking could also result from the printing of a positive 
image from a negative containing airbell markings similar to those 
described under "3" above; namely, "clear spots surrounded by a 
dark ring." 

6. Clear spots with a nucleus of silver halide. The appearance of 
these spots by transmitted light is essentially the same as those 
shown in Fig. 12, although the dark central ring consists largely of 
silver halide instead of metallic silver. The method of formation of 
such spots is probably as follows: During development the airbell 
prevents access of the developer to the emulsion and persists until the 
film is removed from the developer. On re-immersion in the fixing 
bath a small airbell forms where the larger bell previously existed, 
thus protecting the emulsion from fixation. 

The difference between the spots indicated under 5 and 6 is, 
therefore, merely a result of slight wetting of the previously protected 
airbell area with developer immediately before fixing. A nucleus of 
silver halide is produced in one case and a mixture of silver and silver 
halide in the other. 

Factors Affecting the Number of Airbells Formed. — The quantity 
of airbells which may accumulate on the film is determined by the 
following factors: 

1. The manipulation of the rack. This determines: 

a. The rate of immersion of the film. If the film is immersed 
rapidly there is a much greater tendency for it to carry down airbells 
than when immersed slowly. It is important therefore to immerse the 
rack slowly, especially when the end slat touches the surface of the 
developer, because most airbells usually accumulate along the end 

Rapid immersion is also apt to cause foam on the surface of the 
developer, and the small air bubbles constituting the foam attach 
themselves to the film causing airbells. 

b. The time of soaking before removing from the developer. 
Experience has shown that if the film is immersed quickly in the 
developer, allowed to remain submerged for only a few seconds, and 

Rack Marks and A irhell Markings — Crahtree and Ives 109 

is then lifted completely out of the developer and resubmerged, a 
much larger quantity of airbells will be formed than when the film 
was originally immersed. 

Short immersion of the film in the developer followed by exposure 
to the air leaves the film in a partially swollen state, and in this con- 
dition it has a much greater propensity to carry along airbells with 
it on subsequent immersion than the dry or completely swollen film. 
It is usually necessary to allow the film to soak for at least twenty 
to thirty seconds after the first immersion in order to remove this 

c. The degree of agitation of the rack. In many cases airbells can 
be dislodged after the film has been thoroughly soaked by rapid 
agitation of the rack or by slapping the end slat against the surface 
of the developer, though when developing by time it is necessary to 
duplicate the rack agitation precisely and too much rack manipulation 
is not practical. It is preferable to remove the airbells manually as 
described below. 

2. The quantity of grease on the film.— K very slight trace of grease 
or oil on the film will so affect the surface of the emulsion that it has 
a greatly increased tendency to attract airbells. Any appreciable 
quantity of oil or grease will also act as a resist and prevent the access 
of the developer. Preliminary soaking of the film in a solution of 
sodium carbonate will often overcome this tendency (see below) . 

3. The condition of the developer. — Experiments have shown that 
old developer which frequently tends to foam badly has a greater 
tendency to give airbells than new developer. This foaming is the 
result of the presence of decomposed gelatin produced by the action 
of the alkali in the developer on the small particles of emulsion 
removed from the film by abrasion. The effect of the addition of 
ethyl alcohol to such a foaming developer was tried, but no beneficial 
effect was observed by the addition of increasing quantities of the 
alcohol up to 10%. 

Methods of Preventing the Formation of Airhells. — The formation 
of airbells may be prevented as follows: 

1. By soaking the film in water or a solution of sodium carbonate 
{about 2%) before development. This has the effect of thoroughly 
soaking the gelatin, in which condition the propensity for airbells to 
form is a minimum, while the carbonate solution tends to remove 
traces of grease which would otherwise cause airbells and prevent 

110 Transactions of S.M.P.E., March 1926 

access of the developer. The carbonate treatment, however, will not 
remove splashes of mineral oil. 

Any airbells which cling to the film during the soaking process 
can be removed manually by passing a soft camel's hair brush along 
the top slat, reversing the rack in the tank and repeating the process. 

After soaking the film it is very necessary to thoroughly agitate 
the rack for the first minute after immersing in the developer, other- 
wise the liquid carried over by the film will still adhere and cause 
development streaks. 

Soaking is objectionable insofar as it involves an extra operation 
and is really not necessarj^ if the manipulation outlined below is 

2. By taking care not to use developer which is too old and which 
foams badly, by immersing the rack slowly, and by allowing the film 
to remain under the surface of the developer for at least 30 seconds 
before lifting out of the developer for any reason whatever. 

3. By removing the airhells mechanically. — Experience has shown 
that even when the above precautions are taken some airbells may 
still cling to the film, and especially at those parts where the film 
passes over the end slats. The only way to be absolutely certain of 
the absence of airbells at these points is to remove the airbells 
by passing the hand or a soft camel's hair brush along the upper 
and lower slats during the course of development. If this is done 
with reasonable care the film emulsion will not be damaged or 
scratched in any way although no trace of hypo must be present on 
the fingers or brush, otherwise streakiness will result. 

With the usual rack it is not possible to pass the hand across 
the slat owing to interference by the separating pins. This difficulty 
may be overcome by offsetting the pins at an angle of 45° as shown 
in Fig. 4 or by omitting the pins on the slats and placing a bar fitted 
with spacing pins slightly below the end slats. 

Practical Instrnctio7is for Preventing Rack Marks and Airbell 
Markings. — Both rack marks and airbell markings may be largely 
prevented by adhering to the following manipulative procedure 
which should be applied when developing both negative and positive 

1 . Use racks with cylindrical end slats approximately two inches 
in diameter with the spacing pins offset at approximately 45° so 
as to permit of passing the hand or brush along the length of the 
slats so as to dislodge any airbells. 

Rack Marks and Airhell Markings — CraUree and Ives 111 

2. Lower the rack slowly and carefully into the solution, and 
when the lower slat is just below the surface pass the hand quickly 
along its entire length so as to dislodge any airbells. Then completely 
submerge the rack, and in a sunilar manner quickly pass the hand 
across the upper slat and allow the rack to remain submerged for 
thirty seconds. Then allow the rack to float, resubmerge immediately, 
and repeat this operation once every minute during the period of 

3. In case this treatment does not entirely prevent airbells, 
the film should be soaked in water or a 2 percent solution of sodium 
carbonate for three or four minutes before development, and after 
placing in the developer the rack should be moved continuously dur- 
ing the first thirt}^ seconds while submerged in order to prevent 

Rochester, N. Y. 
September 22, 1925. 


Mr. Chanier: Has Mr. Crabtree tried to avoid rack marks by 
circulating the developer; for example, pumping it out at the bottom 
and putting it back at the top of the tank? 

Mr. Briefer: Mr. Crabtree omitted to include the theory of 
airbells running up the sides of the film, but he recommends a remedy 
for it in that the rack must be dropped slowly into the tank. Our 
experience is that the airbells attach themselves between the perfora- 
tions and they then come out and attach themselves to the side. 

Also, we get effects such as Mr. Crabtree has shown when the 
top of the rack is near the top of the developer level. When there 
is plenty of developer above the rack, the markings are very infre- 
quent. We have found a good deal of trouble due to the top of the 
developing tank and the bottom being at different temperatures. 
Manipulation of the rack is the only practical way for the operator 
to prevent irregularities. 

Mr. Ziebarth: Has Mr. Crabtree found that rack marks show 
from the hypo bath if the film is placed in water for a minute between 
the developer and hypo? We have found that the hypo rack marks 
were eliminated in this wsly. 

Mr. Richardson: We have a good manj^ complaints concerning 
new film which will not stay in focus during projection. The picture 

112 Transactions of S.M.P.E., March 1926 

will be alternately in and out of focus on the screen. The only explana- 
tion I have been able to get from laboratory men concerning this 
fault is that it is caused by forced drying, and the fact that in forced 
drying the edge dries quicker, setting up internal stress which causes 
buckling over the aperture during projection. The reason has been 
advanced that it is due to high power light sources used in the first 
run of film when it contained a great deal of moisture. I should like 
to know if you can throw any light on this subject? 

Mr. Crabtree: In reply to Mr. Chanier, I don't know of any 
method of circulating the developer so that you would get equal 
rate of renewal at all points of the rack. We have tried this but it was 
worse than no circulation at all ; it has the same effect as agitation of 
the developer with gas. Unless the flow of gas is equal at every point, 
you get uneven development. 

In regard to Mr. Briefer's remarks: Certainly air is trapped as 
the rack is dropped in the developer, but as it is released, it rises and 
usually does not encroach much on the picture area. Usually the 
airbells are fairly large ones, and once they get started on their 
movement, they are not likely to cling to the film. It is the small 
airbells and particularly those across the top and bottom of the rack 
that cause the trouble. The small airbells which attach themselves 
haphazardly are not of serious moment. The fact that you get more 
rack marks when there is little solution above the top of the film may 
be due, I think, to the fact that the developer tends to oxidize more 
rapidly at the surface and produces more fog. Also, where the 
temperature of the room is greater than that of the developer, so that 
the temperature of the solution at the top would be greater than at the 
middle of the tank, more development takes place at the top of the 
rack causing uneveness. 

In reply to Mr. Ziebarth, a rinse in water will tend to remove the 
developer, although you have to rinse for two or three minutes to 
prevent fixing bath rack marks entirely. Many laboratories do not 
rinse at all between developing and fixing, in which case agitation in 
the fixing bath is necessary. 

In reply to Mr. Richardson, the "in and out of focus" effect 
is due to the buckling of imperfectly dried film under the heat of the 
projector. In the case of film which is rapidly dried at too high a 
temperature, only the outer skin on the gelatin coating is dried, and 
when the film is later subjected to the heat of the projector it buckles 
shghtly in the gate causing the effect in question. 


L. C. Porter and A. C. Roy* 

MODERN theatrical performances are being lighted largely by 
projected light. For this work, many types and sizes of incan- 
descent lamps, spotlights, and floodlights have been developed. 
These same types of projectors also find wide application for the 
lighting of pageants, dance halls, and many other similar institutions. 
The one unit, however, where the arc lamp spot has reigned supreme 
has been in the high power spot. Where a long throw is used, and a 
small intense spot of uniform distribution is required, the Mazda 
lamp has been unable to compete with the arc. This has been due to 
several reasons, primarily the greater concentration of light source 
obtained with the crater of the carbon arc, its high brilliancy, and the 
lack of a lens system especially adapted to the incandescent lamp. 
About a year ago, the authors set out to overcome these condi- 
tions and build a spotlight using a Mazda lamp as a light source 
that could successfully compete with the arc; especially the D.C. 
arc. In order to find out what we were trying to compete with, we 
secured a number of the best spotlights on the market and made 
photometric distribution curves of their beams, concentrated to the 
smallest spots, and also spread out to the maximum floods. D.C. spots 
were used, as the A.C. ones gave much lower beam candlepower than 
D.C. for the same current consumption. A summary of those tests 
shows the following results: 

Beam Candlepower 

Light Source 




Lens Focus 



C. P. Spread 

25 Amp. D.C.arc 





11,000 30° 

50 " " " " 






70 " " " " 





35,000 43° 

400 W 115 V.Mazda 





5,000 20° 

000 " " " " 





6,000 30° 

Experience has shown that the light of the Mazda lamp lies more 
nearly in that portion of the spectrum to which the eye is most 

* Commercial Engineering Department of Edison Lamp Works, Harrison, 
New Jerse}^ 


114 Transactions of S.M.P.E., March 1926 

sensitive (yellow-green) than that of the arc. This, together with 
the steadiness of the illumination from the Mazda lamps, gives an 
apparent equal intensity value for the two illuminants when the 
actual foot candle intensity of the incandescent lamp is appreciably 
lower than that of the arc. It seemed probable, therefore, that if an 
incandescent lamp spot could be built that would produce a spot of 
uniform intensity, and of about five or six hundred thousand candle- 
power, it would better any arc spotlight and be fully as effective as 
D.C. spots up to 50 ampere capacity. 

In attempting to build such a spot, we realized that the ordinary 
coiled wire filament light source was unsuitable. A lamp of this 
nature, when placed at the focal point of a lens system to obtain 
the maximum beam candlepower, threw an enlarged image of the 
filament coils in the spot, giving it a streaky appearance. To over- 
come this, we used a tungsten ribbon as a light source. In order to 
increase the brilliancy of the ribbon to a maximum, it was crimped, 
so that by cross reflection between the crimps the apparent brilliancy 
of the source is increased. 

A ribbon of this type has a rather low resistance and, therefore, 
consumes a high current. The area from which a lens system collects 
light is small ; this means a fairly short filament is all that can be 
utilized. In other words, a low voltage, high amperage lamp. Various 
sizes and shapes of light source were experimented with, but the one 
that has been finally chosen as itiost satisfactory is an 11 volt, 140 
ampere lamp in a T-24 bulb; 13|" overall length, 3'^ diameter, 1\" 
light center length having a special two prong base, No. 1838. This 
base is necessitated by the high current which is too great to be 
carried by the common mogul screw base. Two lamps are used so 
that, in case one fails during a performance, the other may be imme- 
diately turned into position (Fig. 1). 

Lamps of this capacity can be most readily operated from trans- 
formers, a standard 120 to 11 volt, 1500 watt sign lighting transformer 
being well suited to the purpose. 

A starting resistance is necessary with these high current lamps 
to prevent the "overshooting" of the current burning out the fila- 
ment. A "no-voltage" release A.C. motor starting box is provided 
for this purpose and is mounted upon the base of the spotlight. 

Study of the spotlights on the market showed at once that they 
used condensers of relatively long focal length, which would pick up 
but a^mall percentage of the available light flux from a Mazda lamp. 

Spotlight Usi)ig Mazda Lamp — Porter and Roy 


AVe therefore adopted the short focus aspheric condensers which had 
been developed for use with Mazda lamps in motion picture projec- 
tors. In order to pick up all of the light that these condensers were 
able to collect, we used an 8" diameter, 15" focus piano convex lens 
in the end of the spothght housing. The special lens system was 
fitted into a standard housing of a well known make. 

Fig. 1. 

With this combination we obtained a nice smooth spot of uni- 
form intensity and about 700,000 beam candlepower. We thought 
the problem was solved. The spot, however, being really an enlarged 
image of the ribbon filament, was somewhat elliptical instead of 
round. Test of the spotlight in a theatre developed the fact that the 
high priced artists objected to appearing in an elliptical spot. They 
preferred a round spot. In order to obtain this round spot, and also 
to provide an easier method of control of the size of the spot, an iris 
diaphragm was added in front of the aspheric condenser. The lamp. 


Transactions of S.M.P.E., March 1926 

aspheric condenser, and iris diaphragm were mounted as one unit 
on a carriage that could be moved forward and back, thus varying the 

Fig. 2. 

Spotlight U si fig Mazda Lamp — Porter and Roy 117 

distance between the piano lens in the end of the spotlight, and the 
light source (Fig. 2 and Fig. 4). 

This diaphragm cuts down the intensity of the spot a little, the 
average being 575,000 candlepower for the concentrated spot of 2° 
spread, and 45,000 for the flood of 14° spread. The diaphragm pro- 
duces a clean cut, round spot which is free from the usual red color 

Fig. 3. — Illustrating variation in size of spot obtainable with the incandescent 


fringe around the edge. This spot can even be concentrated to such 
an extent as to be just the size of a person's head at 150', something 
that is not possible with the arc spots now on the market (Fig. 3). 

The operation of this spotlight is extremely simple. After closing 


Transactions of S.M.P.E., March 1926 

the switch, the handle of the starting box is moved from starting to 
running position, and the lamp is ready for use. 

Fig. 4 — The completed spotlight. 

There are no carbons to adjust, no sputtering and fussing, nor 
time spent waiting for a crater to form on the positive carbon. 

Spotlight Using Mazda Lamp — Porter and Roy 119 

By simply turning a small knob attached b}' bevel gears to the 
diaphragm, the size of the spot of light upon the stage is varied from 
a small head spot to about one half the width of the usual stage. 
For flooding, a slight forward movement of the "lamp carriage" is 
necessar}^ to cover the full width of the stage. Contrast this with the 
continual shifting of the arc lamp in order to accomplish the same 
result. Once lighted, the Mazda lamp requires no further attention, 
while the arc lamp must be watched and adjusted continually. 

Economy of Current Consumption 

The 50 ampere arc, when operated from a 120 volt line with the 
usual resistance units, consumes about 6000 watts. 

If a motor generator set is employed, a potential of about 70 volts 
is generated, and after passing through the necessary resistance units, 
about 3500 watts are consumed. 

The Mazda lamp requires but 1500 watts for the same apparent 

Quality and Quantity of Light Produced hy the Mazda Outfit 

The color of the spot of light produced by the Mazda lamp is 
soft and pleasing, and is not harsh and cold like that of the carbon 

This spot, therefore, offers all the inherent convenience of an 
incandescent lamp, such as cleanliness, reliabihty, steadiness, ease 
of control, and economy of operation. It should be a great boon in 
theatrical work, and for places where lighting lines are already too 
heavily loaded to permit of the addition of a 5 or 6 kilowatt arc 


Mr. Richardsox: Mr. Porter, you have a low voltage, high 
amperage proposition there, and any slight change in voltage would 
enormously affect the amperage. How do you handle that? I noticed 
apparently in two slides that your collector lens was longer than the 
converging lens: apparently, you have a two lens condenser. Why is 
that if it is true? In the last slide, in your light distribution on the 
medium and small spots — could we have that shde put on again? — 
(slide projected). As I understand this, while you get an amazingly 
even distribution on a floodlight, you get a bright center with a 
relatively dim edge in the spot. Another thing I noticed was that you 
say, for instance, seven hundred thousand beam candle power. 

120 Transactions of S.M.P.E., March 1926 

Do you mean the candle power of the entire beam and, if so, why is 
the flood so much less? I would say that in theatrical work it has 
always been my impression, and I should like to hear from Mr. Deni- 
son on this, that the spotlight with a sharp edge is not desirable; 
it gives the impression of a hole cut in the slide. I believe the diffused 
edge is better. 

Mr. Crabtree: What is the relative value of the ribbon com- 
pared with the cylindrical filament? 

Dr. Hickman: There seems to be a tendency at the present time 
for all forms of searchlights to converge in two widely different 
directions. There is the mirror arc projector, the mirror spotlight, 
and the automobile head lamp, which have unanimously come to 
the use of a simple mirror or collecting lens and nothing else, of 
parabolic surface, and these give a reasonably sharp spot. On the 
other hand, there are the complicated condensing systems which work 
with a diaphragm and a second set of lenses. The effective light is 
only the small cone collected in front of the source and everything 
else is wasted, and the photographic candle power is cut down by the 
many glasses that the light has to penetrate. I should like to ask 
the lecturer if he could give us some idea of why the complicated 
system has been adopted and why the simple mirror arc has been 

Mr. Beggs: What is the average life of the lamps? 

Mr. Powrie: Has any use been made of the lamp for photo- 
graphic work in the studio? It might be particularly adapted for 
color motion pictures. 

Mr. Porter: In regard to the variation in voltage on the lamps, 
it is true that a change in voltage affects the candle power in the 
same way as it does ordinary incandescent lamps, but most of the 
city lines are held within 1 per cent or 2 per cent, and the c.p. varia- 
tions caused by this small fluctuation is scarcely noticeable on the 
screen. A variation of 2 per cent does not materially reduce the life 
of the lamp. 

With regard to the double lens condenser system, we use this 
to pick up a greater solid angle of light. 

In regard to the distribution curves showing a bright center, 
it is true that the center is higher than the edge. This is true with any 
spotlight unless it is out of focus. As to where the edge is, this is 
difficult to determine. The edge of the spot is not absolutely sharp; 
you can't lay a pencil point on it and say, "That is the edge." If it is 

Spotlight Using Mazda Lamp — Porter and Roy 121 

desirable to have it fade off even more gradually, that is easy to 

With regard to the life of the lamps, the ribbon filament lamps 
have a life of about 60 hours. That is along the general life policy of 
incandescent projection lamps in which we strive for intrinsic bril- 
liancy rather than life. 

Answering Dr. Hickman as to why single mirrors are used in 
the large searchlights and parabolic reflectors and not in spotlights, 
the answer is that in the spotlight you must have a unit which can 
be changed rapidly from a concentrated beam to a wide spread flood, 
and you can't do this with the single mirror. 

With regard to the use of a spherical mirror behind the lamp; 
that is practical with the wire type filament, but with the ribbon 
you don't gain much with the mirror. By reflecting the image back 
onto the ribbon itself, the temperature of the ribbon is increased, 
and you only save a very little energy. It would be possible to make 
an apparent larger light source by reflecting the image just above 
the filament, but this seems scarcely worth while for this type of 
lamp. Mirrors deteriorate fairly rapidly, and it doesn't seem worth 
while to fuss with them. 

In regard to the use of the spotlight in studios, we have not 
tried it. We are not in the spotlight business, don't manufacture 
them, and don't intend to, but we wanted to find out whether an 
incandescent lamp can be applied to high power spotlight work. We 
hope some one will build spots along this line, and we should be glad 
to assist anyone who wants to do it. 

Dr. Hickman: The reason I raised the question was that I was 
shown a large number of spotlights in the U.F.A. studios in Berlin. 
They were using sizes from two to six feet in diameter with small 
plane mirror units about three inches square arranged within a 
parabolic metal cage so that the entire assembly formed a parabolic 
mirror with linear facets. One got an enormous light flux spot with 
a brilliant center and soft fading away at the edges. I believe they 
got very efficient lighting by the invention, though I am not sure 
that they were exploiting it. I think they were simply using it 
themselves, and I wondered whether any experimenting had been 
done here along that line. 

Mr. Porter: We have experimented with the lamps for search- 
light work but have not tried them with long focus mirrors for 
spotlight work. 


S. E. Sheppard and S. S. Sweet 

IN AN earlier paper on this subject^ the effect of scratches on the 
strength of film support, not coated with emulsion or processed, 
was discussed. It was concluded from the measurements that the 
"principal effect of a scratch is due to its depth" reducing the effective 
thickness, and "the idea sometimes expressed that the mechanical 
strength of such materials as support and similar plastics is greatly 
dependent upon superficial scratches, and a surface skin does not hold 
for motion picture film support." In the discussion the point was 
raised whether the age of the film and its brittleness would not change 
the matter, so that scratches would have relatively more effect. A 
further study has now been made on processed film brought to equi- 
librium with an atmosphere of definite temperature and humidity. 






Fig. 1. — Diagram of stress — strain curve of film support. 

In order to understand the values tabulated it is necessary to 
reproduce the diagrammatic representation of the characteristic 
stress-strain curve for film. (Fig. 1). The meaning of the total and 
permanent e ongation at the breaking load will be clear. The strength 
measurements were made with a pendulum tester fitted with an 
automatic recording device so that the stretch-load curve could be 
plotted at any convenient speed of loading. (Fig. 2). 
' 1 Trans. S.M.P.E., May, 1924, p. 102. 


Effect of Scratches and Cuts — Sheppard and Sweet 


Scratches were made by an apparatus designed to draw the film 
at constant rate under a point bearing a fixed load. 

Experimental Results. — In the first series processed positive mo- 
tion picture film was conditioned at 30, 50, and 80 per cent relative 
humidity at 70° F., scratched under different loads, the scratch ex- 
tending from edge to edge, on the support side. 

Fig. 2. — Stress and elongation testing machine. 

Nitrate Base Film 35 mm. 


30 per cent R.H. 

50 per cent R.H. 

80 per cent R.H 


Breaking Load 



Breaking Load 


11.6 kg 



9.1 kg 







^ 11.81 











Transactions of S.M.P.E., March 1926 

Acetate Base 

Film 35 mm. 


30 per cent R.H. 

50 per cent R.H. 

80 per cent R.H, 


Breaking Load 

Breaking Load 

Breaking Load 


12.35 kg 

13.0 kg 

8.5 kg 

















In these tests scratches began to be visible at about 100 gms load. 
Up to 500 gms load the break did not necessarily ocurr at the scratched 
place. This corresponds with the fact that these films showed little 
weakening by scratches until loads of 900 gms or more were applied. 

These results on emulsion coated processed film, some months 
old, show to an even greater degree than the former ones with raw 
film support, that only very deep scratches seriously affect the strength. 
Folding tests showed a similar behavior, although the effect of in- 
creasing scratch load was somewhat more marked. 

Processed Nitrate Film 


30 per cent R.H. 

50 per cent R.H. 

80 per cent R.H, 



of Folds 

No. of Folds 


of Folds 


















. 15 



Processed Acetate Film 


30 per cent R.H. 

50 per cent R.H. 

80 per cent R.H 



of Folds 

No. of Folds 


of Folds 

















J 270 




This increased effect of scratches as shown by the decrease in 
number of folds with scratch load was, however, only observed when 
the scratch crossed the perforations. When the scratch was made 
between the perforations, not touching them, there was practically 
no effect on the folds within the limits of the experimental conditions. 

The folding tester used was a new one designed in this laboratory ; 
the folds do not necessarily correspond with the Schopper folds, 
although they agree relatively with hand folding tests. 

Effect of Scratches and Cuts — Sheppard and Sweet 


Effect of Scratches on Elongation. — In an interesting paper pre- 
sented at the Spring meeting of the Society in 1924 by Mr. M. 
Brief er,2 it is remarked that "even a sHght nick, so sKght as to be 
imperceptible to the naked eye, wir shorten the elongation curve 
fifty per cent and more. A very light scratch on the celluloid side, if 
it reaches the edges of the films, will have the same effect." Tests 
were made measuring the whole elastic curve after scratches had 
been applied. 

Processed Nitrate Film 35 mm. 

at 50 per cent R.H. and 70° F. 












11.0 gms 

31 % = 5.9 




19 %=3.6 




15 % = 2.8 




11.5% = 2.2 




7.5% = 1.4 


Processed Acetate Film 35 mm. 

at 50% R.H. 

and 70°F. 

Total . 











12.0 kg. 

(2.7 =15%) 

1.3 cms 



4.35 = 23% 




3.5 =18% 




2.4 =12% • 




2.4 =12% 


See also Fig. 3. 

These results, and still more the original curves, some of which 
are shown in Fig. 3 bear out Mr. Briefer's statement, in so far as 
showing that the effect of scratches is much more marked on the 
elongation than on the breaking load or strength. That is, the effect 
of the scratch is first shown in the period of plastic deformation, so 
that the elongation is reduced, although the breaking load may not 
be affected. 

In these experiments the scratches were made on the support 
side. The previous series had scratches made on both the support 
and gelatin side. No difference was observed in the breaking load in 

2 Trans. S.M.P.E., May, 1924, p. 177. 


Transactions of S.M.P.E., March 1926 

either case, but as this material did not show great sensitivity to 
scratches, it is possible that a difference might show in some cases. 

Effect of Nicks in the Film. — Carefully selected processed film 
with smooth edges was nicked to different depths with a safety razor 
blade. Stock films processed several months past were used. 



Depth of Nick 




mm ins. 




12.8 kg 

6.0 = 31 % 


.05 .002 


1.0= 5.2% 


.10 .004 


1.1= 5.8% 


.20 .008 


1.0= 5.2% 


.30 .012 


0.7= 3.5% 


Effect of scratches on elongation and breaking load. 

Nicks of the order of .002 inches are scarcely perceptible, but the 
effect on the elongation appears to be immediate and more marked 
than that of scratches. 

■ ^Effect of Processing on Scratch Resistance of Film. — Some freshly 
coated unprocessed nitrate base film, 35 mm was given strength tests 
at various humidities. . 

Effect of Scratches and Cuts — Sheppard and Sweet 127 





per cent 






11.4 kg 

2 cms. =10.5% 

.5 cms 




5.6 =29 % 





4.0 =21 % 



Scratch resistance tests on this raw fihii conditioned three days 
at 30 per cent R.H. at 70° F. showed very slight effect of scratches 
on either the breaking load or the elongation up to loads of 900 gms. 
This indifference of the elongation is not necessarity in contradiction 
with the previous results, because at this low relative humidity the 
elongation has already been very much reduced, and in this condition 
the material appears to be less susceptible to scratch damage. 

Folding tests on this raw but well dried film three days at 30% 
R.H.) showed some effect of scratching but not very pronounced. 

Scratch load 100 500 900 1270 gms 

Folds 46 31 26 27 24 

This film was then processed and tested at R.H. 50 per cent at 
70° F. It was then stored at 150° F. for hours, and strength and fold- 
ing tests made for different scratch loads. 

At R.H. 50 per cent Stored at 150°F. 
Breaking load 12.5 kg 14.5 kg 

Total elongation 3.9 cms =20.5 2.2 cms 

Permanent elongation 2 . 2 cms 1.0 cms 

Scratch Breaking Total Permanent 

Load Load Elongation Elongation Folds 

gms 14.5 kg 2.2 cms 1.0 cms 17 

100 14.2 2.6 1.2 18 

500 14.3 1.8 14 

900 14.2 2.7 1.25 15 

1270 12.6 1.7 .4 10 

This material was made relatively brittle by oven heating, as 
showm by a reduction of the folds from 40-46 down to 17, but did not 
appear to be very much affected b}^ scratches until very high loads 
were reached. 

Conclusions. — Examination of processed films has on the whole 
confirmed previous conclusions as to the effect of scratches. There 
appears to be little effect of scratches upon the strength until com- 
paratively deep scratches are produced, and this indifference is in- 
creased rather than lessened, as the film becomes older and hardened. 
Films with a high elongation have this markedly reduced by even 

128 Transactions of S.M.P.E., March 1926 

slight scratches, which do not much affect the breaking load, but 
when the elongation is reduced, as by heat, even this effect becomes 
much less apparent. 


Mr. Denison: My experience with the effect of scratches on 
film both new and old is that we rarely, if ever, have to discard a print 
on account of scratches; that is, scratches in the film do not shorten 
the life of the print. Our only concern is to protect the perforations, 
for practically every print is discarded on account of mutilated per- 
forations. We have marked brittle prints that had fractured perfora- 
tions and kept them in service, and it was surprising how long these 
prints lasted. It appears that most prints fracture in a very short 
time, but in spite of this fact the fracture does not seem to get any 
worse. This is probably due to the drying or seasoning of the film. 
No doubt scratches in the region of the perforations such as are caused 
by emulsion depositing on the shoes of the projector will shorten the 
life of the film considerably, but we have yet to find that ordinary 
scratches affect the life of the print. 

Mr. John Jones: Do I understand that the scratches were 
longitudinal and was not the film perforated? 

Mr. Crabtree: I think it would be interesting to have measure- 
ments on the effect on the film strength of treating the scratched 
film with any of the various media supposed to eliminate scratches. 

Mr. Richardson:-! am not sure I quite understand just what 
the Doctor has in mind. I am Unable to see how longitudinal scratch- 
ing, which is to all intents and purposes the only kind encountered 
in practice, appreciably weakens the film stock. It is harmful because 
the scratches fill with dirt, become opaque, and cause what is termed 
"rain." From the viewpoint of projection, the only weakness of the 
film, provided it be film stock of normal thickness, is found in the 
sprocket holes. I cannot agree with Mr. Denison that sprocket hole 
fractures do not tend to get worse once they are mad.e. I believe 
Mr. Denison did not give suflacient consideration to the fact that 
even though the initial fracture acts to impart a certain degree of 
"springiness" to the edge of the sprocket hole, still, if there be exces- 
sive tension at the aperture of the projector, as is too often the case, 
the tendency will be to increase the fracture, or, if the tension excess 
be. sufficient, to tear away entirely the weakened division between 
two holes. Longitudinal scratches, I must insist, do not weaken the 

Effect of Scratches and Cuts — Sheppard and Sweet 129 

film stock appreciably, and traverse scratching to all intents and 
purposes does not exist. 

Dr. Sheppard: Do you mean scratches across or along the 

Mr. Denison: When I spoke of no appreciable increase in the 
fracture, I meant generally. We have had prints which went to pieces 
on the first six or seven runs, but generally this is not true. In most 
cases we are able to play out all the dates in the territory. 

Dr. Hickman: It seems that the nicks in the edge of the film 
apparently have given contradictory results at various times accord- 
ing to Dr. Sheppard. I should like to know whether all his tests have 
concerned longitudinal strain, because a scratch will split suddenly 
with quite a slight side strain. 

Dr. Sheppard: With regard to Mr. Denison's remarks, first 
of all, I am glad his experience is in agreement with our experimental 
results in that scratching does not affect the using quality of the film ; 
that is, mechanically. I am not referring to the optical behavior of 
the film. I took up this work because statements had been made that 
the breaking of the film depended on quite small scratches on the 
exterior skin. 

With regard to the perforation break, I think that couples up 
with the last remark made by Dr. Hickman. It will depend enor- 
mously on whether the film gets a twist to it, or whether the pull is 
directly on it. If the film breaks so, when we are looking at the per- 
foration sideways like this (drawing), we shall get a small piece acting 
as a spring and affording take-up for the rest of the pull, and it may 
be that the seasoning effect is more connected with the formation of 
such a spring than with a change in the properties of the material. 
That is merely a possibility, and I do not say that seasoning does not 
take place. 

Mr. Jones raised a question as to the direction of the scratches. 
I am sorry I did not make it clear that in this case all the scratches 
were made across the width of the film, from edge to edge, or between 
perforations. In the previous paper we dealt with scratches made 
longitudinally with the length of the film. We are dealing with the 
most extreme case — a scratch from edge to edge — and we found that 
scratches impinging on a perforation are likely to be dangerous, 
while those from edge to edge were not so. 

As regards Mr. Crab tree's suggestion that the effect of covering 
solutions be taken up, I think some little work might be done on this, 

130 Transactions of S.M.P.E., March 1926 

but I do not think that as such it will be very profitable. I started 
this work merely as an entering wedge. The question of scratches as 
such is beginning to exhaust its value; it appears that the practical 
man is in agreement with the laboratory, but whether covering solu- 
tions of this kind cover the behavior of edge injuries is, I think, worthy 
of experimental investigation. 

Mr. Richardson's question with regard to longitudinal scratches 
is, I think, definitely answered. 

Coming to Dr. Hickman's remarks, the question as to the direc- 
tion of the stress applied with regard to the nick is unquestionably 
of great importance. In all the pull down tests the stress was applied 
transverse to the nick. In the case of the folding tests, probably twist 
occurs with any machine. That is worth following up. 

Mr. Richardson: How is film going to get that kind of a scratch 
in practice? 

Dr. Sheppard: You do have scratches in different directions. 
I took the worst possible. Formerly, we investigated scratches lying 
in different directions. 

Mr. Richardson: The effect of such scratching would, I beheve, 
to all intents and purposes be negligible as regards weakening the film. 

Mr. Denison: I follow film conditions very closely, and I agree 
with Mr. Richardson that we don't get transverse folds that ever 
affect the film. In V-ing film it might occur occasionally. You are 
more apt to get it in rewinding, and if the projector is in fairly good 
condition, you don't get a twist sufficient to damage the film. At 
least, I am stating that on my past experience only. 

Dr. Sheppard I am entirely open to suggestion and conviction 
on the matter of twist. 

Mr. Richardson: In the projector you may or may not have a 
side pull between the upper magazine and the upper sprocket. There 
can be no side pull except where there are crookedly made splices 
after the film has left the upper sprocket, because thereafter every- 
thing is in perfect alignment, and that alignment cannot be changed. 
On one popular professional projector it is possible to get the upper 
sprocket and upper magazine out of alignment, in which case there 
vvould be some side pull, which might develop into a very hard pull 
under some conditions. 

Dr. Sheppard: I was not considering only the projection mach- 
ine. . There are processing machines in which the film passes around 
a spiral so that there is twist produced on it, and the relation of twist 

Effects of Scratches and Cuts — Sheppard and Sweet 131 

to the liability of the film to become nicked is of probable importance. 
In all the film considered there was no twist. Mr. Denison's denial 
of the film reacting to scratches is all right, because I started the 
matter with an open mind; I didn't start with the belief that there 
is a great deal of trouble with scratches. I do not regret the work or 
consider it wasted because the result is largely negative. 


Earl J. Denison^ 

DURING the past ten years the mechanical processes involved in 
the making of motion pictures have, for the most part, been 
subjected to critical analyses followed by changes and improve- 
ments which have resulted in increased efficiency. Processes of 
major importance, such as the perforation of the film, the taking of 
the pictures, and the making of positiv